Kato must write 60 percent of a 20-page report by tomorrow. Kato wants to determine the number of pages that he needs to write by tomorrow. Kato’s work is shown below.

Question

Step 1: Write 60 percent as a ratio. StartFraction part Over whole EndFraction = StartFraction 60 Over 100 EndFraction
Step 2: Write an equivalent ratio that has the answer in the numerator and 20 in the denominator.
Step 3: 100 divided by 20 = 5
Step 4: 60(5) = 180

What mistake did Kato make?
In Step 1, Kato should have written the ratio as StartFraction 100 Over 60 EndFraction.
In Step 2, Kato should have put 20 in the numerator.
In Step 3, Kato should have multiplied 100 by 5.
In Step 4, Kato should have divided 60 by 5.

Answer 1

Kato made a mistake in Step 4.

In Step 1, Kato correctly represented 60 percent as a ratio of 60 out of 100.

In Step 2, Kato correctly set up an equivalent ratio with 20 in the denominator to find out how many pages correspond to 60 percent of the report.

In Step 3, Kato correctly calculated that 100 divided by 20 is 5.

However, in Step 4, Kato incorrectly multiplied 60 by 5, which gives 300, instead of correctly taking 60 divided by the ratio (in this case, 5) to find how many pages Kato needs to write.

The correct calculation for Step 4 should be:

60 divided by 5 equals 12.

Thus, Kato should have determined that he needs to write 12 pages by tomorrow.

So the correct option is: In Step 4, Kato should have divided 60 by 5.