Question

Q3. The total of the ages of A, B and C is 80 years. What was the total of their ages three years ago ? 0 77 o 83 o 71 o89​

Answer 1

Answer:

If their total ages now 80 then three years ago their total ages would be 80-3 = 77.

Answer 2

Given :- The total of the ages of A, B and C is 80 years. What was the total of their ages three years ago ?

A) 77

B) 83

C) 71

D) 89

Solution :-

Let us assume that,

→ Present age of A = a years

→ Present age of B = b years

→ Present age of C = c years

so,

→ Total ages of (A + B + C) = 80 years

→ (a + b + c) = 80 --------- Eqn.(1)

now,

→ Age of A three years ago = Present age - 3 = (a - 3) years

→ Age of B three years ago = Present age - 3 = (b - 3) years

→ Age of C three years ago = Present age - 3 = (b - 3) years

then,

→ Total ages of (A + B + C) three years ago = (a - 3) + (b - 3) + (c - 3) = a + b + c - 3 - 3 - 3 = (a + b + c) - 9 -------- Eqn.(2)

putting value of Eqn.(1) in Eqn.(2) we get,

→ Total ages of (A + B + C) three years ago = 80 - 9 = 71 years (Ans.)

Therefore, the total of their ages three years ago was Option (c) 71 years .

Shortcut :-

→ Total age three years ago = Total present age - 3 years before * 3 people = 80 - 3 * 3 = 71 years .

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