1.  Peter invested an amount of ₹ 12,000 at the rate of 10 p.c.p.a. simple interest and another amount at the rate of 20 p.c.p.a. simple interest. The total interest earned at the end of one year on the total amount invested became 14 p.c.p.a. Find the total amount invested.
A. ₹ 20,000
B. ₹ 22,000
C. ₹ 24,000
D. ₹ 25,000
E. None of these

Answer: Option A

Explanation:

Let the second amount be ₹ X. Then,

12000 x 10 x 1 + X x 20 x 1
100 100

= (12000 + X) x 14 x 1


100

<=> 12000 + 20X = 168000 + 14X
<=> 6X = 48000
<=> X = 8000.

Total investment = ₹ (12000 + 8000)

= ₹ 20000.