SOLUTION: respected sir, 1] A student first reduced a certain number by 20% and then increased it again by 20%. If the difference between the last number and the original number was 8, th

Algebra ->  Percentage-and-ratio-word-problems -> SOLUTION: respected sir, 1] A student first reduced a certain number by 20% and then increased it again by 20%. If the difference between the last number and the original number was 8, th      Log On


   



Question 198253: respected sir,
1] A student first reduced a certain number by 20% and then increased it again by 20%. If the difference between the last number and the original number was 8, then the original number was:

plz help me to solve this % sum...
thank u...

Answer by arallie(162) About Me  (Show Source):
You can put this solution on YOUR website!
I change the 20% into 80%,when reducing, because it makes it easier to work with.
ie%28x-.2x%29=%281-.2%29x=.8x
A student first reduced a certain number (henseforth called x) by 20%...
.8x
...and then increased it again by 20%.
1.2%28.8x%29
If the difference between the last number and the original number was 8...
1.2%28.8x%29-.8x=8
.96x-.8x=8
.16x=8
x=50
...then the original number was:
50