Question

The difference between the interest obtained for ₹1000 at 12% per annum for 3 years and that for ₹1500 at 8% per annum for $1\frac{1}{2}$ years is

(a) ₹360
(b) ₹300
(c) ₹180
(d) ₹200

Answer 1

It is given that,
Sum (P₁) = ₹1000
Rate (R₁) = 12%
Time (T₁) = 3 years

$$\begin{gathered} I_1=\frac{P_1\times R_1\times T_1}{100} \\ =\frac{1000\times 12\times 3}{100} \\ =360....\left(1\right) \end{gathered}$$

Sum (P₂) = ₹1500
Rate (R₂) = 8%
Time (T₂) = $1\frac{1}{2}$ years = $\frac{3}{2}$ years

$$\begin{gathered} I_2=\frac{P_2\times R_2\times T_2}{100} \\ =\frac{1500\times 8\times 3}{100\times 2} \\ =180....\left(2\right) \end{gathered}$$

Subtracting (2) from (1), we get
$I_2-I_1=360-180=180$

Hence, the correct option is (c).