CAT (QA) PYQs

At a certain simple rate of interest, a given sum amounts to Rs 13920 in 3 years, and to Rs 18960 in 6 years and 6 months. If the same given sum had been invested for 2 years at the same rate as before but with interest compounded every 6 months, then the total interest earned, in rupees, would have been nearest to

Amala, Bina, and Gouri invest money in the ratio $3: 4: 5$ in fixed deposits having respective annual interest rates in the ratio $6: 5:4$. What is their total interest income (in Rs) after a year, if Bina's interest income exceeds Amala's by Rs $250$?

Alex invested his savings in two parts. The simple interest earned on the first part at $15 \%$ per annum for $4$ years is the same as the simple interest earned on the second part at $12 \%$ per annum for $3$ years. Then, the percentage of his savings invested in the first part is