Question 955170
Jack is four times older than mark. In six years mark will be half of jacks age. How old will jack be eight years from now?
M=Mark's age; J=jack's age=4M
J=4M
J+6=2(M+6) Substitute for J
4M+6=2M+12 Subtract (2m+6) from each side.
2M=6 Divide each side by 2
M=3 Mark is 3 years old.
J=4M=4(3)=12 Jack is 12 years old.
In 8 yrs J+8-12+8=20 ANSWER: In 8 years, Jack will be 20 years old.
CHECK:
J+6=2(M+6)
12+6=2(3+6)
18=18