Question

A trust fund has invested Rs. 30,000 in two different types of bonds which pays 5% and 7% interest

respectively. Determine how much amount is invested in each type of bond if trust obtains an annual

total interest of Rs. 1600.​

Answer 1

The amount is invested in each type of bond if trust obtains an annual total interest of Rs. 1600 is Rs. 25,000 & Rs. 5000 respectively.

Step-by-step explanation:

The total amount invested in two different types of bonds = Rs. 30,000  

So, let the amount invested in the first bond be Rs. “x” then in the second bond will be Rs. “(30,000 – x)” .

Rate of interest given for the first bond = 5%

Rate of interest given for the second bond = 7%

An annual total interest earned by the trust = Rs. 1600

The formula required for solving the interest in this case is,

S.I. = $\frac{P*R*T}{100}$

Based on the formula we can write the equation as,

[(x*1*5)/100] + [{(30,000-x)*1*7}/100] = 1600

⇒ 5x + 2,10,000 – 7x = 1,60,000

⇒ 2x = 2,10,000 – 1,60,000

⇒ x = 50,000/2  

⇒ x = 25,000 ← principal amount in which the bond pays 5% interest

And,

(30,000 - x) = 30,000 – 25,000 = 5000 ← principal amount in which the bond pays 7% interest