Question

Jack is 27 years older than Susan. In 5 years, he will be 4 times as old as she is.

a. Find the present ages of Jack and Susan.
b. What calculations would you do to check if your answer is correct?

Answer 1

susan´s age=4

jack´s age=31

Explanation:

Hello!

To solve the first part of this problem we must propose a system of equations of 2 x2, that is to say two equations with two unknowns where

J = is the age of jack

S = susan's age

with the above the following two equations are inferred

ecuation 1

J=S+27

ecuation 2

(J+5)=4(s+5)

J=4S+20-5

J=4S+15

now to solve we subtract equation 1 from equation 2 as follows

J=4S + 15

-

J=S + 27

___________

0=4S-S+15-27

0=3S-12

`S=(12)/(3)=4`

susan is 4 years old

now we use the ecuation number 1

J=S+27

J=4+27=31

jack is 31 years old

b.

Finally, to verify that the answer is correct, we replace the ages of jack and susan in equation 2.

(J+5)=4(s+5)

(31+5)=4(4+5)

36=36

as the equation is the same means that our answer is correct