Question

A sum of money amounted to Rs. 31,200 at 4% per annum in 5 years. Find the original sum.

Answer 1

A=p(1+Tr/100)

31200=p(1+20/100)

p=31200×100/120

=26000

Answer 2

✬ Sum = Rs 26,000 ✬

Step-by-step explanation:

Given:

• Total amount of money (A) = Rs 31,200.
• Rate of interest (R) = 4%.
• Time (T) = 5 years.

To Find:

• What is the original sum i.e principal (P) ?

Solution: Let the principal be P.

As we know that

★ Interest = ( P $\times$ R $\times$ T/100 ) ★

$\implies{\rm }$ I = ( P $\times$ 4 $\times$ 5/100 )

$\implies{\rm }$ I = 20P/100

$\implies{\rm }$ I = P/5

Now,

★ Amount = (Principal + Interest) ★

$\implies{\rm }$ 31200 = (P + P/5)

$\implies{\rm }$ 31200 = (5P + P/5)

$\implies{\rm }$ 31200 $\times$ 5 = 6P

$\implies{\rm }$ 156000 = 6P

$\implies{\rm }$ 156000/4 = P

$\implies{\rm }$ Rs 26000 = Principal

Hence, The original sum was Rs 26,000.