Question

Find the rate of intrest when rs 800 fetches rs 130 as SI in 2 yrs 6 months

Answer 1

$\sf Given :$

Principal money, P = 800

Simple interest on this money, S.I. = 130

Time for interest, t = 2 yrs 6 months = 2.5 yrs

To find :

Rate of Interest, R =?

• Formula required :

Formula to calculate Simple interest

$➪\purple{\bigstar}\boxed{\sf{S.I.=\dfrac{P\times R \times t}{100}}}★$

[ Where S.I. in simple interest on Principal money P, Rate of interest per annum R and t being time for interest ]

Solution :

Using formula for SImple interest

$\implies\sf{S.I.=\dfrac{P \times R \times t }{100}}$

$\implies\sf{130=\dfrac{800 \times R \times 2.5 }{100}}$

$\implies\sf{130=8 \times R \times 2.5}$

$\implies\sf{130=20 \times R }$

$\implies\sf{R=\dfrac{130}{20}}$

$\implies\boxed{\boxed{\large{\purple{\sf{R=6.5\;\;\%}}}}} \;\;\;\purple{\bigstar}$

• Therefore,

Rate of interest is 6.5 %.

Answer 2

Answer:

SI = PNR/100

P = 800 Rs

SI = 130 Rs

T = 2 years 6 months = 5/2 years

130 = 800×5×R/2×100

R = 13/2 = 6.5 % per annum