I can t solve an easy question- Percent.

[nyotamalaika]

The output of a factory was increased by 10% to keep up with rising demand. To handle the holiday rush, his new out put was increased by 20%. By approximately what percent would the output now have to be decreased in order to restore the original output?

a. 20 %
b. 24 %
c. 30 %
d. 32 %
e. 70 %

According to the book the answer is 24 %, but keep finding 32 %. It seems easy.

[givemeanid]

Let original output be 100.
After 10% increase: 110
After further 20% increase: 110 + 0.2(110) = 132

To restore the output to original level, it needs to be decrease by 32.
% = 32*100/132 = 24.24%

Remember, that you are decreasing the output by 32 from 132. Not 100. 32 is the 'tricks/traps' answer.

[nyotamalaika]

Let original output be 100.
After 10% increase: 110
After further 20% increase: 110 + 0.2(110) = 132

To restore the output to original level, it needs to be decrease by 32.
% = 32*100/132 = 24.24%

Remember, that you are decreasing the output by 32 from 132. Not 100. 32 is the 'tricks/traps' answer.

Thanks Giveme