A sum of money was lent in two parts in the ratio 4 : 5 for 4 years and 5 years respectively, both at the rate of 8% per annum simple interest. If the difference between the interests earned from the two parts is ₹ 4680, then what was the total sum lent(in ₹)?

58500

Money was lent in two parts in the ratio of 4:5

first part

Principal (P)1 = 4x                             

Rate (R)1  = 8%

Time (T)1 = 4 years

second part

Principal (P)2 = 5x

Rate (R)2 = 8%

Time (T)2 = 5 years

ATQ, Difference of Interest = Rs 4680

I2 - I1 = 4680

\(\frac{P2×R2×T2}{100}\) - \(\frac{P1×R1×T1}{100}\) = 4680

\(\frac{5x×8×5}{100}\) - \(\frac{4x×8×4}{100}\) = 4680

\(\frac{200x}{100}\) - \(\frac{128x}{100}\) = 4680

\(\frac{72x}{100}\) = 4680

x = \(\frac{4680×100}{72}\)

x = 6500

P1+P2

4x+5x = 9x

9×6500

Rs 58500