give solution

Question

A SHOPKEEPER OFFFERS THREE SUCCESSIVE DISCOUNTS OFF 20%,15%AND 10%TO HIS CUSTOMER .THE SALES CLERK WISHES TO AVOID HAVING TO MAKE SO MANY CALCULATIONS AND WORK OUT A SINGLE PERCENTAGE . WHAT IS THE SINGLE PERCENTAGE TO BE DEDUCTED FROM THE MARKED PRICE.

Answer is 38.8%

Answer 1

 

20% discount means you pay only 80%

15% discount means you pay only 85% of 80%

0.85*80%=68%

10% discount means you pay only 90% of 68%

0.9*68%=61.2% is what you pay

therefore 100%-61.2%=38.8% discount