A sum is deposited in a bank which gives simple interest. The sum becomes 1.25 times in 3 years. If there is a requirement of ₹7,60,000 after seven years, how much amount (in ₹) should one deposit to fulfill the requirement?

4,80,000

Let Principal = Rs.100

Amount after 3 years = 100 × 1.25 = Rs.125

S.I in 3 years = 125 - 100 = Rs.25

S.I in one year = 25/3

SI in 7 years = 7 × \(\frac{25}{3}\) = \(\frac{175}{3}\)

Amount after 7 years = 100 + \(\frac{175}{3}\) = \(\frac{475}{3}\)

ATQ,

⇒ \(\frac{475}{3}\)R = 7,60,000

⇒ 1R = 7,60,000 × \(\frac{3}{475}\)

⇒ Principal = 100R = 7,60,000 × \(\frac{3}{475}\) × 100 = Rs.4,80,000/-