Question

What is the single discount equivalent to two successive discounts of 20% and 10%? *

a) 28%

b) 30%

c) 29%

d) 27%

​

Answer 1

Answer:

Single discount =

$(100 - 100 \times (1 - \frac{20}{100} )(1 - \frac{10}{100} ))\% \\ = (100 - 100 \times \frac{4}{5} \times \frac{9}{10} )\% \\ = (100 - 72)\% \\ = 28\%$