Question

ra 250 is invested today it will become rs 750 in 19 year what is compound interest option 1st 6% 2nd 7% 3rd 8% 4th 9% ​

Answer 1

Rs. 250 is invested today, it will become Rs. 750 in 19 years.

To find : the rate of compound interest is....

solution : here principal, P = 250 Rs.

final amount, A = 750 Rs.

time, n = 19 years

using formula,

A = P(1 + r/100)ⁿ

750 = 250(1 + r/100)^19

⇒750/250 = (1 + r/100)^19

⇒3 = (1 + r/100)^19

taking log both sides, we get,

⇒log3 = 19log(1 + r/100)

⇒log3/19 = log(1 + r/100)

⇒0.025 = log(1 + r/100)

⇒10^(0.025) = 1 + r/100

⇒1.06 = 1 + r/100

⇒r = 6%

Therefore the 1st option is correct choice.