A sum of money at simple interest amounts to Rs. 2240 in 2 years and to Rs. 2600 in 5 years. What is the principal amount?
1000
1500
2000
2500
Explanation:
SI for 3 years = 2600-2240 = 360
SI for 2 year 360/3 $\times$ 2 = 240
principal = 2240 - 240 = 2000.