A trust caring for handicapped children gets Rs 30,000 every month from its donors The trust spends half of - Maths - Matrices

Question

A trust caring for handicapped children gets Rs 30,000 every month
from its donors The trust spends half of the funds received for
medical and educational care of the children and for that it
charges2% of the spent amount from them , and deposits the balance
amount in privatebank to get the money multiplied so that in future
the trust goes on functioning regularly What percent of interest
should the trust get from the bank to get a total of Rs 1,800 every
month?
Use matrix method, to find the rate of interest Do you think people
should donateto such trusts?

Anuradha Sharma · Accepted Answer

Here is the answer :

Out of Rs 30000, trust spends half for medical and educational care
So, amount deposited in Private bank = Rs 15000The trust charges 2% of the money spent  for medical and educational care
Earning of the trust from the above charges = 2% of Rs 15000 = Rs 300Let the earning of the trust from the above charges be Rs x and the earning from the interest obtained from the bank = Rs Ynow, X + Y = 1800X = 300The above equations in matrix form is,1110XY = 1800300⇒XY = 1110-11800300⇒XY =  0-1-11-11800300⇒XY = 011-11800300⇒XY = 3001500⇒X = 300; Y = 1500Let the monthly rate of interest be R%Now, R% of Rs 15000 = Rs 1500⇒R = 10