Question

Veeru invested Rs 10000 at 5% simple annual interest, and exactly after two years, Joy invested Rs 8000 at 10% simple annual interest. How many years after Veeru's investment, will their balances, i.e., principal plus accumulated interest, be equal?

(TITA)

Accepted Answer

12. Let $t$ be the number of years after Veeru's investment when their balances become equal. - Veeru's balance after $t$ years: $$A_V = 10000 + 10000 	imes 0.05 	imes t = 10000 + 500t$$ - Joy invests 2 years later, so Joy's money earns interest for $(t - 2)$ years: $$A_J = 8000 + 8000 	imes 0.10 	imes (t - 2) = 8000 + 800(t - 2) = 800t + 6400$$ Setting $A_V = A_J$: $$10000 + 500t = 800t + 6400$$ $$300t = 3600 \implies t = 12$$ Thus, their balances will be equal 12 years after Veeru's investment.

Equal balances of Veeru and Joy

Explanation

Practise this under exam conditions