Question

03. Calculate the simple interest on 1400 at 3% interest per annum for six months.​

Answer 1

Principal = ₹1400

rate% = 3%

time = 6 months

To find : Simple interest.

simpleinterest = ptr/100

where p=≥ principal, t=≥ time and r=≥ rate.

si = 1400×3×1/2×100

by reducing to the lowest terms :

si = 7 ×3

Simple interest = ₹21

Amount = Principal + interest

Amount = ₹1400 + ₹21

Amount = ₹1421

t = 100×si/pr

p = si×100/tr

r = 100× si/pt

Answer 2

Given :-

• Principal = ₹1400
• Rate = 3 %
• Time = 6 months

Formula to use :-

$\boxed{\longrightarrow \sf Simple\:Interest = \dfrac{Principal \times rate \times time}{100} }$

Answer :-

We know that,

1 year = 12 months

∴ 6 months = $\sf \cfrac{1}{2}$ years.

Substituting the values,

$\implies \sf Simple\:Interest = \dfrac{1400 \times 3 \times \dfrac{1}{2} }{100}$

$\implies \sf Simple\:Interest =\bigg( 1400 \times 3 \times \dfrac{1}{2} \bigg)\div 100$

Reducing to the lowest terms,

$\implies \sf Simple\: Interest = (700 \times 3)\div 100$

$\implies \sf Simple\:Interest = 2100 \times \dfrac{1}{100}$

$\implies \sf Simple\:Interest = 21\not0\not0\times \dfrac{1}{1\not0\not0}$

$\implies \sf Simple\:Interest = 21$

The Simple Interest on a sum of ₹1400 for 6 months is ₹21

Some more formulas :-

$\longrightarrow \sf Principal = \dfrac{Simple interest\times 100 }{Time \times Rate}$

$\longrightarrow \sf Rate = \dfrac{Simple\:interest \times 100 }{Time \times Principal}$

$\longrightarrow \sf Time = \dfrac{Simple interest\times 100}{Principal \times Rate}$