Question

ratio of the ages of Prithvi and Robin is 4:7

Answer 1

Answer:

The ratio of the present ages of A:B::4:7, or 7A = 4B, or A = (4/7)B …(1). Ten years hence the ratio of their ages will be (A+10):(B+10)::3:4, or 4(A+10) .

Answer 2

Answer:

The ratio of the present ages of A:B::4:7, or

7A = 4B, or

A = (4/7)B …(1).

Ten years hence the ratio of their ages will be (A+10):(B+10)::3:4, or

4(A+10) = 3(B+10), or

4A = 3B+30–40 = 3B-10, or

A = (3/4)B -2.5 …(2)

Equate (1) and (2)

A = (4/7)B = (3/4)B -2.5. LCM of 7 and 4 is 28, So we have

16B = 21B -2.5*28 = 21B- 70, or

21B - 16B = 70, or

5B = 70, or

B = 14. From (1), A = (4/7)*14 = 8.

So the ratio of A’s age 5 years later to the present age of B will be 13:14.

Step-by-step explanation:

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