Explanation

First, find the value of 150 increased by 60%: (150)(1.6) = 240. If 240 were then decreased by y percent, the result would be 192.

Because 240 is decreased by 48 to get 192, the question can be rephrased: 48 is what percent of 240?

\(48=\frac{x}{100}\times 240\).

\(x=20\).

Given

1. 150 were increased by 60%

= 150 * 160%

= 150 * (160/100)

= 240.

2. decreased by y % . Final result is 192.

Difference = ( 240 - 192) = 48

SO, we know that this 48 once was the part of 240. So ,we can find out the value of y in terms of 240.

(48/240)*100

= 20%

The best answer is A.

Could you please explain when we can do approximation and when we can not?

150 were increased by 60% = \(150(1+\frac{60}{100})=15*16=240\)..

decreased by y percent means \(240(1-\frac{y}{100})=192......240(100-y)=19200......100-y=\frac{19200}{240}=80......y=100-80=20\)

A

Not this>>> 240-190 = 50.

This will be: \(240-192 = 48.\)

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