Question 213145
500*1.1*1.2 = 660
.
check,,,500 *10% = 500*.1=50,added,,,,500+50 = 550
.
550 * 20% = 550 *.2=110, added,,,,,550 +110 = 660,,,,ok
.
.
note adding  10%  is  the  same  as  multiplying  by 1.1 ( 1 + .10)
.
and  adding  20%  is  the  same  as  multiplying  by 1.2( 1 + .20)
.