1. If 1200 rupees grows to 1584 rupees in 4 years with simple interest, then how much principal amount will grow to 2800 rupees in 5 years?

(a) ₹ 2000 (b) ₹ 1800 (c) ₹ 2500 (d) ₹ 2100

2. If some amount triples in 30 years with simple interest, what is the rate of interest?

(a) 6\(\cfrac{2}{3}\)% (b) 10% (c) 15% (d) 6%

3. If a principal amount doubles in 20 years at a certain simple interest rate, then in how many years will it triple at the same simple interest rate?

4. If a principal doubles in 20 years with simple interest, then at the same simple interest rate, the principal will become four times in –

(a) 30 years (b) 40 years (c) 80 years (d) 60 years

5. If a certain principal amount triples in 15 years at simple interest, then the annual rate of simple interest will be —

(a) \(13\frac{1}{3}\%\) (b) \(12\frac{1}{3}\%\) (c) \(11\frac{1}{3}\%\) (d) \(10\frac{1}{3}\%\)

6. If a principal becomes five times through simple interest in 10 years, then in how many years will it become nine times the original amount including interest?

(a) 18 (b) 20 (c) 25 (d) 30

7. If a principal amount doubles in 20 years at a certain simple interest rate, then at the same rate, the principal will triple in – ?

(a) 30 years (b) 35 years (c) 45 years (d) 40 years

8. If a certain amount of money triples in 20 years, then at the same simple interest rate, in how many years will it double?