Question

Maths
A invests RS 8000 and B invests Rs 11000 at the same rate of interest per annum. If at the end of 3 yrs , B get Rs 720 more interest than A; find the rate of interest. ​

Answer 1

Answer:

Step-by-step explanation:

Required formula:

S.I. =  

A invested = Rs. 8000

B invested = Rs. 11000

Time period of investment for both A & B, T = 3 years

Let the rate of interest in both the investment be “R”% and the interest earned by A and B be denoted as “Ia” & “Ib” respectively.

Interest earned by A after 3 years:

Ia =  = 240R …… (i)

And,

Interest earned by B after 3 years:

Ib =  = 330R …… (ii)

It is given that at the end of 3 years the interest earned by B is Rs. 720 more than the interest earned by A, so we can write the eq. as,

Ib = Ia + 720

⇒ 330R = 240R + 720 ……. [substituting values from (i) & (ii)]

⇒ 90R = 720

⇒ R = 720/90

⇒ R = 8%

Thus, the rate of interest is 8%.