Question

The sum of 3 times the age of son and the age of his father is 110.If 3 times the age of his father is added to the age of son we get 170 find their ages

Answer 1

Answer:

Write the two descriptions as equations:

110 = f + 3×s — eq. 1

170 = s + 3×f — eq. 2

f = 110 - (3 ×s) — eq. 1 rearranged

170 = s +3×(110 - 3×s) — eq. 1 plugged into eq. 2

170 = s +( 330 - 9×s) — eq. 2 reduced

170 = 330 - 8×s — eq. 2 reduced

8×s = = 330 - 170 — eq. 2 reduced

8×s = 160 — eq. 2 reduced

s = 160 / 8 — eq. 2 reduced

s = 20 — eq. 2 reduced - the son is 20 yrs old.

110 = f + 3 ×20 — plugging son’s age into eq. 1

f = 110 - 60 — eq. 1 reduced

f = 50 — eq. 1 reduced — the father is 50 yrs old