Carlo correctly answered 36 out 40 questions on an exam correctly. Which ratio is equivalent to carlos result?

Question

Answers are A. 72:100

B. 76:100

C. 80:100

D. 90:100

We need help working out the problem.

Answer 1

It sometimes helps to understand what the problem is asking or what the problem is intended to teach.

 

With this problem, I see immediately that all the possible answers are a ratio of 100.  That means we need to find X such that:

      36/40 = X/100

 

We could cross-multiply, multiply both sides by 100, reduce fractions, etc.  Let's just reduce fractions first, then multiply by 100:

       36/40 = 9/40

So,

         9/10 = X/100

          90 = X      (multiply both sides by 100)

Answer D.

Answer 2

We now that a percent is a number out of 100.

 

 

36 / 40 = x  / 100

 

 

Solve for x.   Cross multiply.

 

 

40x = 3600

   x = 90

 

 

His equivalent ratio is 90/100.