Question

A sum of Rs. 8,000 is lent partially at 10% and remaining at 2% per annum. If the yearly interest on the sum is 6% per annum.find the amount lent at 10% per annum.
1. Rs. 6000
2. Rs. 1000
3. Rs. 7000
4. Rs. 4000

Answer 1

Correct Answer - Option 4 : Rs. 4000

Given

Total amount lent = Rs. 8000

Rate of interest = 10% and 2%

Formula used

Simple interest = (p × r × t)/100

Where p, r and t are principal, rate and time respectively

Calculation

Let Rs x is lent at 10% and Rs. (8000 - x) is lent at 2% rate

(8000 × 6 × t)/100 = (x × 10 × t)/100 + [(8000 - x) × 2 × t]/100

⇒ 480t = (10xt + 16000 t - 2xt)/100

⇒ 48000t = 8xt + 16000t

⇒ 32000t = 8xt

⇒ 32000/8 = x

⇒ 4000 = x

∴ Amount lent at 10% per annum is Rs. 4000