Question

Solve the proportion
5/x = 4/8
A. 2
B. 6
C. 8
D. 10

Answer 1

Cross-multiply for a result of:

40=4x

Divide by 4 to see that x=10. D is the correct answer.

Answer 2

5/x = 4/8

Simplify the fraction 4/8

Divide both the numerator and denominator by 4 to get 1/2

5/x = 1/2

Now, we cross multiply: a/b = c/d ⇒ ad = bc

5/x = 1/2
1(x) = 5(2)
x = 10

Your final answer is D. 10.