The rate of simple interest per annum of bank being decreased from 5% to \(3\frac{1}{2}\%\), the annual income of a person from interest was less by Rs. 105. The sum deposited at the bank was
1). Rs. 7,000
2). Rs. 6,000
3). Rs. 7,200
4). Rs. 6,800
We know that, SI = P × R × T/100
Where, P = Principal, R = % rate of interest, T = time in years
Here, SI1 = P × R1 × T/100 and SI2 = P × R2 × T/100
SI1 – SI2 = P × (R1 – R2) × T/100
Change in the interest rate = 1.5%
Change in the interest obtained = 105
⇒ 105 = P × 1.5/100 = 7000