Question

In Kendra’s class, 40 percent of the students earned an A on the math test. Twenty students earned an A. Kendra needs to find out how many students are in her class. Kendra’s work is shown below.

40 / 2 = 20
_________
100 x 2 = 200
what mistake did kendra make? (the / is meant as a division symbol)
A. Kendra should have multiplied by 4 in both the numerator and the denominator.
B. Kendra should have divided by 2 instead of multiplying by 2 in the denominator.
C. Kendra should have added 40 and 20.
D. Kendra should have the part to whole equation written as 100/40 (100 over 40)

Answer 1

The correct answer is B) she should have divided by 2 instead of multiplying by 2 in the denominator.

Answer 2

B. Kendra should have divided by 2 instead of multiplying by 2 in the denominator.

Explanation:

In Kendra’s class, 40 percent of the students earned an A on the math test.

Let the total students in the class be = x

So, as per the situation given, we can say that

`0.40* x=20`

x = 50

Hence, there are 50 students in the class.

We can cross check this as:

`0.4*50=20`

So, Kendra surely did a mistake.

Kendra should have divided 100 by 2. But she multiplied by 2.