Consider, R (Ramesh) invested 10x and S (Suresh) invested 12x.
R got 10y back in 8 months and S got 18y back in p months.
8 months -> 10y/10x = y/x returns on investment
1 month -> y/8x return on investment
return amount = duration * returns * investment amount
Therefore, for S -
18y = p * (y/8x) * 12x
Solving for p, we get p = 12 months.
Answer :- D