Aman invests Rs. 8000 at some rate of interest. Being simple interest the money doubles in 5 years. Raj sees this and invests Rs. 6250 for 3 years at same rate of interest. How much interest does Raj get?

Rs. 3750

Formulae for SI = \(\frac{\text{P Χ R Χ T} }{ 100}\) 

According to the question:

8000 (As the sum gets doubled) = \(\frac{\text{8000 Χ R Χ 5} }{ 100}\) 

8000 = \(\frac{\text{40000 Χ R} }{ 100}\) 

8000 = 400R

R = \(\frac{8000 }{400 }\)

R = 20%

Investment by Raj for 3 years:

SI = \(\frac{\text{6250 Χ 20 Χ 3} }{ 100}\) 

SI = 3750