Question

Fill in the blanks in the table.

	Principal	Rate of interest (p.c.p.a.)	Time	Interest	Amount
(i)	4200	7%	3 years	......	......
(ii)	......	6%	4 years	1200	......
(iii)	8000	5%	......	800	......
(iv)	......	5%	......	6000	18000
(v)	......	$2\frac{1}{2}\%$	5 years	2400	......

Answer 1

(i)
Given:
Principal (P) = 4200 rupees,
Rate of interest (R) = 7%
Time (T) = 3 years
Total interest (I) = $\frac{P\times R\times T}{100}$
= $\frac{4200\times 7\times 3}{100}$
= 882 rupees
Total Amount = P + I
= 4200 + 882
= 5082 rupees

(ii)

Given:
Total interest (I) = 1200 rupess
Rate of interest (R) = 6%
Time (T) = 4 years
Principal (P) = $\frac{I\times 100}{R\times T}$
= $\frac{1200\times 100}{6\times 4}$
= 5000 rupees
Total Amount = P + I
= 5000 + 1200
= 6200 rupees

(iii)
​
Given:
Principal (P) = 8000 rupees
Total interest (I) = 800 rupess
Rate of interest (R) = 5%
Time (T) = $\frac{I\times 100}{P\times R}$
= $\frac{800\times 100}{8000\times 5}$
= 2 years
Total Amount = P + I
= 8000 + 800
= 8800 rupees

(iv)
​
Given:
Principal (P) = 8000 rupees
Total interest (I) = 6000 rupess
Now, Principal (P) = Total Amount − I
= 18000 − 6000
= 12000 rupees​
Rate of interest (R) = 5%
Time (T) = $\frac{I\times 100}{P\times R}$
= $\frac{6000\times 100}{12000\times 5}$
= 10 years

(v)

Given:
Total interest (I) = 2400 rupess
Rate of interest (R) = $2\frac{1}{2}$%
= $\frac{5}{2}$%
Time (T) = 5 years
Principal (P) = $\frac{I\times 100}{R\times T}$
= $\frac{2400\times 100\times 2}{5\times 5}$
= 19200 rupees
Total Amount = P + I
= 19200 + 2400
= 21600 rupees

	Principal	Rate of interest (p.c.p.a.)	Time	Interest	Amount
(i)	4200	7%	3 years	882	5082
(ii)	5000	6%	4 years	1200	6200
(iii)	8000	5%	2 years	800	8800
(iv)	12000	5%	10 years	6000	18000
(v)	19200	$2\frac{1}{2}\%$	5 years	2400	21600