Question

Wilson paints 40% of a bookcase in 20 minutes how much more time will it take him to finish the bookcase?

Answer 1

30 minutes

Explanation:

He paints 40% of the bookcase in 20 minutes.

The rest of the bookcase is 100% - 40% = 60%.

60% of the bookcase still needs painting.

40% is to 20 minutes as 60% is to x minutes

40/20 = 60/x

Reduce the fraction on the left side.

2 = 60/x

Multiply both sides by x.

2x = 60

Divide both sides by 2.

x = 30

Answer: 30 minutes

Answer 2

30 minutes

Explanation:

First you can break down the percent and the time into a fraction

You can divide it by 2

so 2%/1 (2% in 1 minute)

Then you find the amount of time it would take to paint the whole bookcase

2 * 100 = 50

So time to paint the whole bookcase would be 50

50 - 20 = 30