Question

the music store is having a 15% off sale on all classical music cds. lyell has a coupon for 20% off any classical music cd. how much will lyell save on a classical music cd that has a price of $23.99? a. $7.20 b. $7.68 c. $8.40 d. $9.60

Answer 1

This is a problem of consecutive discounts. First discount is 15% and second discount is 20%.

Tha way of solving this problem is by multipliying by the two factors.

When you discount 15% the factor is 100% - 15% = 85% = 0.85

When you discount 20% the factor is 100% - 20% = 80% = 0.80

The the combined factor is: 0.85*0.80 = 0.68

Now apply that discount over the original price to obtain the final price: $23.99 * 0.68 = 16.31

Which means that Lyell saved $ 25.99 - $16.31 = $7.68 (option b).

Answer 2

Off sale:
$23.99 * 0.15 = $3.5985
$23.99 - $3.5985 = $20.3915
With more 20% off:
$20.3915 * 0.2 = $4.0743
$3.5958 + $4.0783 = $7.6768 ≈ $7.68
Answer: B ) $7.68