If the total discount on the cost of skis for the Ski Store was 35% after trade discounts of 18%, 9% 3% ..?

Let the bill amount be 100X

100X * 0.82 * 0*91 * 0.97 * d = 65X

72.3814X *d = 65X

d = 65 /72.3814 = 0.898

d = 10.2 % ANSWER

If the total discount on the cost of skis for the Ski Store was 35% after trade discounts

so the total amount of discounts is 35% of the cost

18%, 9% & 3%

if they are added together

30%

so the invoice discount would be 5%

if they are pancaked

18%*9%*3%

18*1.09*1.03

20.2086%

so the invoice discount would be

35-20.2086

14.7914

14.8%

So first she gets a discount of 18, then 9, then 3. And then the prompt pmt discount.

100-18 = 82 is the cost after 18%

82 - (82*0.09) = 74.62 this is after the 9%

74.62 - (74.62*0.03) = 72.38 is the cost after the 3% discount

100 - 72.38 = 27.62 is the total discounts so far. And she got 35%, so your answer is:

35 - 27.62 = 7.38% was the prompt payment discount.

You just cascade the discounts, as follows

If you have a discount of a% then the factor you multiply with is (1 - a / 100)

So in this case, you have ( 1 - 0.35) (1 - 0.18) (1 - 0.09) (1 - 1.03) = 0.65 (0.82) (0.91) (0.97) = 0.47

So the overall equivalent discount is 100*(1 - 0.47) = 53 %