The present ages of M and N are in the ratio of 6 : 4. Five years ago, their ages were in the ratio of 5: 3. How old is M now?

Question: The present ages of M and N are in the ratio of 6 : 4. Five years ago, their ages were in the ratio of 5: 3. How old is M now?

Solution:
ধরি,
M ও N এর বর্তমান বয়স যথাক্রমে = 6x এবং 4x

5 বছর আগে,
(M - 5)/(N - 5) = 5/3
⇒ (6x - 5)/(4x - 5) = 5/3
⇒ 3(6x - 5) = 5(4x - 5)
⇒ 18x - 15 = 20x - 25
⇒ 18x - 20x = - 25 + 15
⇒ - 2x = - 10
⇒ x = 5

∴ M এর বর্তমান বয়স
M = 6x
= 6 × 5
= 30 বছর

∴ M এর বর্তমান বয়স = 30 বছর