Question

At present time a man is four times as his son. 6 years ago he was 10 times as old. find their present age.

Answer 1

Define some variables. Write two true equations.

Answer 2

we can write this as a system of equations
x = 4y
x - 6 =10y
x = dad's age
y = son's age

Answer 3

i messed up the second equation, it should be
x - 6 = 10(y - 6)

Answer 4

x=4y
x-6=10(y-6)

Answer 5

since x = 4y that means x - 6 = 10(y - 6) can also be written as
4y - 6 = 10(y - 6)
solve for y
4y - 6 = 10y - 60
54 = 6y
y = 9

Answer 6

yeh
x=4y
x=10y-54
4y=10y-54............6y=54.......y=9......x=36

Answer 7

if the son is 9 years old, according to our first equation
x = 4y
the dad should be 4(9) years old or 36 years old