Find a single discount (approximately) equal to three consecutive discounts of 7%, 10% and 15%.

Solution

Successive discounts: 7%, 10%, 15%

Equivalent single discount formula:

Equivalent price factor
= (1 - 0.07)(1 - 0.10)(1 - 0.15)

$= 0.93 \times 0.90 \times 0.85$

First multiply:

$0.93 \times 0.90 = 0.837$

Then:

$0.837 \times 0.85 = 0.71145$

So the final price is 71.145% of the marked price.

Equivalent single discount:

100 - 71.145 = 28.855%

Approximately:

28.85%

Correct option: 28.85%