₹ 7,000 earns ₹ 1,400 as interest at 5% per annum. Then the time in this case is:

1. 5 years

2. 2 years

3. 10 years

4. 4 years

Given:

P = ₹ 7,000

R = 5%

S.I. = ₹ 1,400

Let time be $t$ years.

$\because \text{S.I.} = ₹ \Big(\dfrac{P \times R \times T}{100}\Big)\\[1em] \Rightarrow \text{1,400} = ₹ \Big(\dfrac{7,000 \times 5 \times t}{100}\Big)\\[1em] \Rightarrow \text{1,400} = ₹ \dfrac{35,000t}{100}\\[1em] \Rightarrow \text{1,400} = ₹ 350t\\[1em] \Rightarrow t = \dfrac{1,400}{350}\\[1em] \Rightarrow t = 4$

∴ Time = 4 years

Hence, option 4 is the correct option.