A person lent Rs. 23000 to B for 3 years and Rs. 19000 to C for 4 years on simple interest at the same rate of interest and received Rs. 3625 in all from both of them as interest. What is the annual rate of interest?

2.5 percent

Money lent to B:

⇒ Principle(P) = 23000, Rate(R) = R%, Time(T)= 3 years

Money lent to C:

⇒ P = 19000, R = R%, T = 4 years

ATQ,

⇒ I₁ + I₂ = 3625

⇒ \(\frac{P_1\;×\;R_1\;×\;T_1}{100}\) + \(\frac{P_2\;×\;R_2\;×\;T_2}{100}\) = 3625

⇒ \(\frac{23000\;×\;R\;×\;3}{100}\) + \(\frac{19000\;×\;R\;×\;4}{100}\) = 3625

⇒ 690 R + 760 R = 3625

⇒ 1450 R = 3625

⇒ R = \(\frac{3625}{1450}\) = 2.5%