Question

A sum amounts to ₹2652 in 6 years at 5% of interest per year.
Find:- a) the sum
b) the time in which the same sum will double itself at the same rate of interest​

Answer 1

Answer:

a. 2040 rupees

b. 20year

Step-by-step explanation:

let sum = p

time(t) = 6 year

rate of interest (r) = 5%

sum with interest = 2652

or interest (I) = 2652-p ( where p is sum)

we know that ptr/100=I

or p×5×6/100= 2652-p

or 3p/10 +p =2652

or 13p/10= 2652

or p = 2652× 10/13

or p = 2040

* the sum is 2040 rupees

for finding year

ptr/100=p ( sum will double mean sum +interst= 2sum)

or p ×t × 5= p×100

or t=100/5= 20 year

* in 20 year sum will double