Question 241960
cost is equal to 40.
original price is equal to 40 + .3*40 = 52
sale price = 40 + .105*40 = 44.20
original price minus sale price = 52 - 44.2 = 7.8
discount percent = discount divided by original price = 7.8/52 = .15 * 100% = 15%


in formula form, this would be shown as follows:


c = cost
p = original price
s = sale price
d = discount off of original price
r = discount rate off of original price
r% = r * 100%


p = c + .3*c
s = c + .105*c
d = p - s
r = d/p
r% = r * 100%


put into numbers:


c = 40
p = 40 + .3*40 = 40 + 12 = 52
s = c + .105*c = 40 + 4.2 = 44.2
d = p - s = 52 - 44.2 = 7.8
r = d/p = 7.8/52 = .15
r% = .15 * 100% = 15%


he buys it at 40.
he puts it on sale at 52.
he discounts it 15% from 52
he sells it at 44.2 and gets a 10.5% profit on the original cost of 40.