A sum of Rs. 1550 was lent partly at 5% and partly at 8% pa simple interest. The total interest received after 5 yr was Rs. 500. Find the ratio of the money lent at 5% to that at 8%?
1. 12 : 17
2. 17 : 12
3. 19 : 12
4. 16 : 15
1. 12 : 17
2. 17 : 12
3. 19 : 12
4. 16 : 15
Correct Answer – Option 4 : 16 : 15
Given:
Sum = Rs. 1550
Rate = 5% and 8%
Time = 5 yrs
SI = Rs. 500
Formula Used:
S.I = P × r × t/100
Calculations:
Let the sum lent at 5% be P
Sum lent at 8% = (1550 – P)
Then, (P × 5 × 5)/100 + [(1550 – P) × 8 × 5] /100 = 500
⇒ 25P – 40P + 1550 × 40 = 50000
⇒ -15P + 62000 = 50000
⇒ -15P = 50000 – 62000
⇒ -15P = -12000
⇒ P = 800
Sum lent at 8% = 1550 – 800 = 750
required ratio = 800 : 750 = 16 : 15.
∴ The ratio of money lent at 5% to that at 8% is 16 : 15.