Question

PLEASE HELP

The ratio of Brenda’s age to Jason’s age is 4:5. In eight years the ratio will be 6:7. How old is Brenda now?
a.
20
c.
28
b.
16
d.
12

Answer 1

Declarations

Let Brenda's age be B

Let Jason's age be J

Equations

`(B)/(J)=(4)/(5)\\ \\ ((B+8))/((J+8)) = (6)/(7)`

Solution

Cross multiply both fractions

5B = 4J (1)

7(B + 8) = 6(J + 8) Remove the brackets on both sides.

7B + 56 = 6J + 48 Subtract 48 from both sides

7B + 56 - 48 = 6J

7B + 8 = 6J (2)

Use Equation (1) to solve for J

5B = 4J Divide by 4

5B/4 = J Pult this result in equation 2

7B + 8 = 6*( 5B/4)

7B + 8 = 30*B/4

7B + 8 = 7.5 B Subtract 7B from both sides.

8 = 7.5B - 7B

8 = 0.5 B Divide by 0.5

B = 8/0.5

B = 16 <<<< Answer