Answer:
John is 48 and Martha is 12
Step-by-step explanation:
John is four times as old as Martha or:
John = 4 × Martha
j=4m
Five years ago the sum of their ages was 50 or:
John - 5 + Martha - 5 = 50
j-5+m-5=50
j+m=60
Substitute Martha for John
4m+m=60
5m=60
m=12
Martha is 12
Substitute 12 for Martha
j+12=60
j=48
John is 48
We can double check this by checking that John is 4 times as old as Martha and that 5 years ago the sum of their ages was 50.
12×4=48
48=48
12-5+48-5=50
7+43=50
50=50
