If a number is added to the numerator of 7/8 and the same number is subtracted from the denominator, the result is 2. Find the number.

Question

The answers are:

A. 1

B. 3

C. 4

D. 2

Answer 1

Hey!

Remember that "a number" in math just means a variable - or a letter used for an unknown number. Let's choose x as our letter. We also know that numerators are the "tops" of fractions and the denominators are "bottoms." The word result indicates that we will have a final answer, so we need an equal sign too! So now we have:

7+x. = 2

8-x

We can easily solve this equation for x! First of all, get rid of the ratio by multiplying by 8-x on both sides. You then will have:

7+x = 2(8-x).

Multiply the right side out and then simplify and use inverses to find x! Let me know if you have questions.

Answer 2

(7+x)/(8-x) = 2

cross multiply

16 -2x = 7 +x

3x = 9

x= 9/3 = 3

x= 3

B is correct

(7+3)/(8-3) = 10/5 = 2