A sum of money becomes Rs. 2000 after 3 years and Rs. 5000 after 6 years on compound interest. The sum is
Let the sum be P and rate be r.
⇒ P (1 + r/100)3 = 2000 ------ (1)
⇒ P (1 + r/100)6 = 5000 ------ (2)
Dividing eq(2) by eq(1), we get,
⇒ (1 + r/100)3 = 5/2 ----- (3)
Putting equation (3) in equation (1)
⇒ P × 5/2 = 2000
∴ P = 2000 × 2/5 = Rs. 800