Question

Samar invested 5000 at 7% and 7000 at 6%. After a certain time, he found that the
difference between the both the interest earned was 350. Find the duration of investments
​

Answer 1

Answer:

5 year

suppose time is t year

suppose the interest is x. when principal is 5000.

for we need ;

5000 X 7 X t / 100 = x

or; 350t = x

suppose the interest is y . when the principal is 7000.

for we need ;

7000 X 6 X t / 100 = y

or; 420t = y

then we need;

y-x= 350

or; 420t - 350t= 350

or; 70t = 350

or, t = 5