Question

In the table below, the rate of interest and the principal are given. Find out, in each case, what would be the interest for one year.

Examples	1	2	3	4	5	6
Rate of interest (p.c.p.a.)	10	14	9	6	3	11
Principal (Rs)	6,000	500	15,000	12,000	25,000	8,000

Answer 1

We know:
$\mathrm{Interest}=\frac{\mathrm{Principal}\times \mathrm{Rate}\mathrm{of}\mathrm{interest}\left(\mathrm{p}.\mathrm{c}.\mathrm{p}.\mathrm{a}.\right)\times \mathrm{Time}\left(\mathrm{in}\mathrm{years}\right)}{100}$

Given: Time = 1 year
The solutions of the subparts are as follows:

(1) Rate of interest = 10 p.c.p.a.
Principal = Rs 6000
Using the above formula, we get:
Interest $=\frac{6000\times 10\times 1}{100}$
$$\begin{gathered} =\frac{60000}{100} \\ =600 \end{gathered}$$

Thus, the interest is Rs 600.

(2) Rate of interest = 14 p.c.p.a.
Principal = Rs 500
Using the above formula, we get:
Interest $=\frac{500\times 14\times 1}{100}$
$$\begin{gathered} =\frac{7000}{100} \\ =70 \end{gathered}$$

Thus, the interest is Rs 70.

(3) Rate of interest = 9 p.c.p.a.
Principal = Rs 15000
Using the above formula, we get:
Interest $=\frac{1500\times 9\times 1}{100}$
$$\begin{gathered} =\frac{135000}{100} \\ =1350 \end{gathered}$$

Thus, the interest is Rs 1350.

(4) Rate of interest = 6 p.c.p.a.
Principal = Rs 12000
Using the above formula, we get:
Interest $=\frac{12000\times 6\times 1}{100}$
$$\begin{gathered} =\frac{72000}{100} \\ =720 \end{gathered}$$

Thus, the interest is Rs 720.

(5) Rate of interest = 3 p.c.p.a.
Principal = Rs 25000
Using the above formula, we get:
Interest$=\frac{25000\times 3\times 1}{100}$
$$\begin{gathered} =\frac{75000}{100} \\ =750 \end{gathered}$$

Thus, the interest is Rs 750.

(6) Rate of interest = 11 p.c.p.a.
Principal = Rs 8000
Using the above formula, we get:
Interest$=\frac{8000\times 11\times 1}{100}$
$$\begin{gathered} =\frac{88000}{100} \\ =880 \end{gathered}$$

Thus, the interest is Rs 880.