A single discount equivalent to discount series 20% , 20% and 10% is = ?

A. 50%

B. 48.4%

C. 42.4%

D. 40.4%

Answer: Option C

Solution(By Examveda Team)

Single equivalent discount for 20% and 20%
$$\eqalign{ & = 20 + 20 - \frac{{20 \times 20}}{{100}} \cr & = 40 - 4 \cr & = 36\% \cr} $$
Single equivalent discount for 36% and 10%
$$\eqalign{ & = 36 + 10 - \frac{{36 \times 10}}{{100}} \cr & = 46 - 3.6 \cr & = 42.4\% \cr} $$