The ratio between the interest obtained from scheme L and M in 6 and 4 years is 4:3 respectively. In scheme L, Rs. 6000 was deposited on simple interest at the rate of (R+2)% per annum. If the simple interest obtained from scheme M after 4 years is Rs. 5400 and initially the amount deposited in scheme M is 50% more than the amount deposited in scheme L, then find out the ratio between the rate of interest per annum in scheme M and L respectively.

Solution

The ratio between the interest obtained from scheme L and M in 6 and 4 years is 4:3 respectively.

If the simple interest obtained from scheme M after 4 years is Rs. 5400.

simple interest obtained from scheme L after 6 years = (5400/3)x4 = Rs. 7200

In scheme L, Rs. 6000 was deposited on simple interest at the rate of (R+2)% per annum.

7200 = 6000x(R+2)%x6

20 = (R+2)    Eq.(i)

initially the amount deposited in scheme M is 50% more than the amount deposited in scheme L.

amount deposited in scheme M = Rs. 6000 of (100+50)%

= Rs. 6000 of 150%

= Rs. 9000

Rate of interest in scheme M = (5400x100)/(9000x4)

= 15%

Ratio between the rate of interest per annum in scheme M and L respectively = 15 : (R+2) [By Eq.(i)]

= 15 : 20

= 3 : 4