Combining hull options
Combining hull options
If I want to design a ship with a light (25% cost), streamlined (+20% cost) hull, what's the order of operations? Do I just add the modifiers for a net 5% cost?

 Lesser Spotted Mongoose
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Re: Combining hull options
The use of the +/ indicates additive, so yes 5%.

 Cosmic Mongoose
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Re: Combining hull options
As per the example of the Heavy Fighter on p102:
50 Dt hull, streamlined(+20%), reinforced(+50%)
Hull cost = 50 × 0.05 × 120% × 150% = MCr 4.5
So, for a streamlined(+20%), light hull(25%)
Hull cost = 50 × 0.05 × 120% × 75% = MCr 2.25
50 Dt hull, streamlined(+20%), reinforced(+50%)
Hull cost = 50 × 0.05 × 120% × 150% = MCr 4.5
So, for a streamlined(+20%), light hull(25%)
Hull cost = 50 × 0.05 × 120% × 75% = MCr 2.25

 Lesser Spotted Mongoose
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Re: Combining hull options
Which is incorrect with the modifiers notation, +20% = 0.2 and 25% =  0.25, not 1.2 and 0.75
The long form of the difference.
50,000 + 20%  25%
50,000 + 10,000  12,500 = 47,500
47,000 * 50 = 2,375,000
2,375,000 / 1,000,000 = 2.375
vs
50,000 * 1.2 * 0.75
50,000 * 0.9 = 45,000
45,000 * 50 = 2,250,000
2,250,000 / 1,000,000 = 2.25
The long form of the difference.
50,000 + 20%  25%
50,000 + 10,000  12,500 = 47,500
47,000 * 50 = 2,375,000
2,375,000 / 1,000,000 = 2.375
vs
50,000 * 1.2 * 0.75
50,000 * 0.9 = 45,000
45,000 * 50 = 2,250,000
2,250,000 / 1,000,000 = 2.25

 Chief Mongoose
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Re: Combining hull options
I don't think there's a canonical ship that goes both up and down, only up.

 Lesser Spotted Mongoose
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Re: Combining hull options
MGT 1st Ed HG Light Carrier, 30kdt Closed hull (10% cost) = 2,700 Mcr
30,000t x 0.1 Mcr = 3,000 Mcr
3,000 x 0.9 = 2,700 Mcr
30,000t x 0.1 Mcr = 3,000 Mcr
3,000 x 0.9 = 2,700 Mcr

 Chief Mongoose
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Re: Combining hull options
In theory, Second supersedes First.

 Lesser Spotted Mongoose
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Re: Combining hull options
I just find it funny that notation is correct in 1st edition and incorrect in 2nd, where its indicated as additive modifiers (+ / ) yet the values used are multiplicative.

 Cosmic Mongoose
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Re: Combining hull options
I don't think we can read the rules to literally, e.g.:
Resolving the double negation this would mean increasing the cost by 25% for an additional 10% Hull points.Light Hull: By decreasing the cost of a hull by 25%, a ship will have its Hull points decreased by 10%.
Are you saying that "increase the cost 25%" would mean anything different from "increase the cost +25%"? That is not a notation I have ever seen.baithammer wrote: ↑ I just find it funny that notation is correct in 1st edition and incorrect in 2nd, where its indicated as additive modifiers (+ / ) yet the values used are multiplicative.

 Lesser Spotted Mongoose
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Re: Combining hull options
The proper structure is increase cost by 25% which is an additive statement versus 125% of the cost which is multiplicative.Are you saying that "increase the cost 25%" would mean anything different from "increase the cost +25%"? That is not a notation I have ever seen.
With the original example you get the following equations.
x + 0.20x 0.25x = x0.05x = 0.95x
Compared to
1.2x * 0.75x = 0.9x

 Cosmic Mongoose
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Re: Combining hull options
I have never heard of that convention, rather the opposite.baithammer wrote: ↑ The proper structure is increase cost by 25% which is an additive statement versus 125% of the cost which is multiplicative.
A simple example would be:
An apple costs $1.00. You get a 10% discount. You add 10% sales tax. What do you pay?
Answer: $1.00 × 90% × 110% = $0.99.
Or:
An apple costs $1.00. The price is increased 10%. The price is then increased 10% again. What is the price?
Answer: $1.00 × 110% × 110% = $1.21.

 Lesser Spotted Mongoose
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Re: Combining hull options
First example is a set of subtotals which can be generalized as multiplicative.
$1.00  $0.10 ( 10% discount) = $0.90
$0.90 + $0.09 (10% Sales Tax) = $0.99
Second one is a bit different.
Since both % are applied to the same base they add together, so 10% + 10% = 20%
$1.00 + $0.10 + $0.10 = $1.20
$1.00  $0.10 ( 10% discount) = $0.90
$0.90 + $0.09 (10% Sales Tax) = $0.99
Second one is a bit different.
Since both % are applied to the same base they add together, so 10% + 10% = 20%
$1.00 + $0.10 + $0.10 = $1.20
Re: Combining hull options
You apply the discount to the base cost and you calculate the tax on the base cost, you then work out the total
apple £1
10% discount 10p
10% tax 10p.
You pay £1 and the government gets its extra 1p in tax
Course if you do tax first the government couldn't care less about the discount.
Personally I would sum all the discounts and additional costs to come up with a final multiplier, otherwise you are going to fudging the order in which you apply them to get the best deal.
apple £1
10% discount 10p
10% tax 10p.
You pay £1 and the government gets its extra 1p in tax
Course if you do tax first the government couldn't care less about the discount.
Personally I would sum all the discounts and additional costs to come up with a final multiplier, otherwise you are going to fudging the order in which you apply them to get the best deal.

 Cosmic Mongoose
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Re: Combining hull options
No. [ https://blog.taxjar.com/salestaxdisco ... romotions/ ]
Sales tax, or more complicated VAT (since £), is calculated on actual price payed, defined depending on jurisdiction.
Multiplication is commutative; order of operations does not matter to the result.
Price payed = $1.00 × 90% × 110% = 110% × 90% × $1.00 = $0.99

 Cosmic Mongoose
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Re: Combining hull options
They are not calculated on the same base:baithammer wrote: ↑ Second one is a bit different.
Since both % are applied to the same base they add together, so 10% + 10% = 20%
$1.00 + $0.10 + $0.10 = $1.20
"An apple costs $1.00." . . . . . . . . . . . . . . . CurrentPrice = $1.00
"The price is increased 10%." . . . . . . . . . . . CurrentPrice = CurrentPrice × 110% = $1.00 × 110% = $1.10
"The price is then increased 10% again." . . .CurrentPrice = CurrentPrice × 110% = $1.10 × 110% = $1.21
"What is the price?" . . . . . . . . . . . . . . . . . . .CurrentPrice is $1.21
If you want to define a base price from which percentages are calculated you have to say so, normally something like: "The base price is $1.00. Increase by 10% of base price, increase by 10% of base price again".
Re: Combining hull options
I apply the cheap option a 10% discount to a drive say. I take it three times.
The drive has a base cost of MCr10.
How much do I pay?
Is it 0.9 x 0.9x 0.9 x 10 = MCr7.29
or is it 0.7 x 10 = MCr7?
The drive has a base cost of MCr10.
How much do I pay?
Is it 0.9 x 0.9x 0.9 x 10 = MCr7.29
or is it 0.7 x 10 = MCr7?

 Lesser Spotted Mongoose
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Re: Combining hull options
10 x 1.3 = 13 Mcr as its an actual multiplicative arrangement. ( Notice its not +10% but just 10% )I apply the cheap option a 10% discount to a drive say. I take it three times.
Which is contradicted by the article you linked, not to mention VAT is often baked in to the price rather than a separate line item.Sales tax, or more complicated VAT (since £), is calculated on actual price payed, defined depending on jurisdiction.
^ The article further points this out in the above.In layman’s terms, that means if the original price of something you sell was $100, but you offer a 50% discount, then the taxable price is $50.

 Cosmic Mongoose
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Re: Combining hull options
Unfortunately undefined in the rules.
The example of the Fleet Courier on p132 says apply them to the base price (additive):
MDrive Thrust 2 (Reduced Size × 3)
Size: 400 Dt × 2% × (1  10%  10%  10% ) = 400 × 2 × 70% = 5.6 Dt
Cost: 5.6 Dt × 2 × 150% = MCr 16.8

 Cosmic Mongoose
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Re: Combining hull options
Sales tax is calculated on actual price payed (including partly payed by someone through a coupon) [except in Texas] {further exceptions...}baithammer wrote: ↑Which is contradicted by the article you linked, not to mention VAT is often baked in to the price rather than a separate line item.Sales tax, or more complicated VAT (since £), is calculated on actual price payed, defined depending on jurisdiction.
The simple case is (quote from the linked article):
With 10% sales tax you pay: $30 × 95% × 110% = $31.35Because discounts are generally offered directly by the retailer and reduce the amount of the sales price and the cash received by the retailer, the sales tax applies to the price after the discount is applied. For example, your normal selling price is $30 but you are offering a 5 percent discount for first time customers. The tax base is $28.50.
VAT is always included in the price, it is defined as a part of the actual price payed, not as an added tax.
Yes, so with 10% sales tax you would pay $100 × 50% × 110% = $55baithammer wrote: ↑^ The article further points this out in the above.In layman’s terms, that means if the original price of something you sell was $100, but you offer a 50% discount, then the taxable price is $50.
Advertised price = $100
Discounted price = $100 × 50% = $50
Payed including tax = $100 × 50% × 110% = $55

 Lesser Spotted Mongoose
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 Joined: Wed May 31, 2017 2:21 am
Re: Combining hull options
Going to give another stab at the difference between the two formulations.
One positive modifier 20% and a negative modifier 25%.
50,000 + 20% 25%
x + 0.2x  0.25x
x  0.05x
 5%
vs
50,000 * 1.2 * 0.75
x * 1.2 * 0.75
x * 0.9
 10%
Note the additives each modify x and then are totaled where as each modifier under the second case are modifying each other regardless of x.
The next example is what you get with two positive modifiers.
50,000 + 20% + 25%
x + 0.2x + 0.25x
x + 0.45x
45%
vs
50,000 * 1.2 * 1.25
x * 1.2 * 1.25
x * 1.5
50%
One positive modifier 20% and a negative modifier 25%.
50,000 + 20% 25%
x + 0.2x  0.25x
x  0.05x
 5%
vs
50,000 * 1.2 * 0.75
x * 1.2 * 0.75
x * 0.9
 10%
Note the additives each modify x and then are totaled where as each modifier under the second case are modifying each other regardless of x.
The next example is what you get with two positive modifiers.
50,000 + 20% + 25%
x + 0.2x + 0.25x
x + 0.45x
45%
vs
50,000 * 1.2 * 1.25
x * 1.2 * 1.25
x * 1.5
50%
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