Question

Raman kept a certain principal in bank for 10 years and received rs 300 as interest. rehman kept the same principle for 7 years. if the rate of interest was 3% p.a for both. find the amount received by rehman after 7 years.

Answer 1

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☞ Given :

Raman's case

Time period = 10 years

Interest = Rs 300

Rate of interest = 3%

Rehman's case

rate of interest = 3%

Time period = 7 years

☆ Required to find :

1. Amount received by Rehman.

✐ Explanation :

In the question we have 2 cases and using the first case hints we have to find the required answer .

In Raman's case we were given with every required value . Using those values we need to find the principal amount this is because the principal amount is equal in both the cases .

So; to find the principal amount we should use a formula that is

$principal \: = \frac{interest \: \times \: 100}{time \: \times \: rate}$

Hence ;

Using the above mentioned formula we can find the principal amount .

Thereby ; using this principal amount in Rehman's case we will find the interest .

Using the formula;

Interest = principal × time × rate ÷ 100

Hence ; we can find the interest .

At last using the formula ;

Amount = principal + Interest

we can find the required answer .

☞ Solution :

✎ Raman's case

Interest = Rs 300

Time period = 10 years

Rate of interest = 3%

principal amount = ?

Hence ;

Using the formula ;

$principal \: = \frac{interest \: \times \: 100}{time \: \times \: rate} \:$

Now substitute the required values .

$principal = \frac{300 \times 100}{10 \times 3} \\ \\ principal = \frac{30000}{30} \\ \\ principal \: = 1000 \: rupees$

Therefore ;

Principal amount is Rs 1000

✎ Rehman's case :

Principal Amount = Rs 1000

Rate of interest = 3%

Time period = 7 years

Interest = ?

Using the formula;

$interest = \frac{principal \times rate \times time}{100}$

Hence,

Substitute the required values we get ;

$interest \: = \frac{1000 \times 3 \times 7}{100} \\ \\ interest = \frac{21000}{100} \\ \\ interest \: = 210 \: rupees$

Therefore;

Interest = 210 rupees .

Hence ;

Amount he will receive is ;

Using the formula;

$amount = principal + interest$

Therefore;

Amount = 1000 + 210

= Rs 1210

Amount received = Rs 1,210