Question 603418
"A man is 8 times as old as his son" ___ m = 8s


"In 5 years he will be only 4 times as old" ___ m + 5 = 4(s + 5)


substituting the equivalent value of m from the 1st equation into the 2nd equation ___ (8s) + 5 = 4s + 20


4s = 15



the answer is not a whole number, which probably means that the numbers in the question need to be changed