Question

the difference between c. i and s. i on 7500 for two years is 12 at the same rate of interest per annum. Find the rate of interest

Answer 1

let the rate be x

s.i = p*r*t/100

$\frac{7500 \times x \times 2}{100}$

$75 \times 2 \times x$

150x is your simple interest

c.i for 1st year= 7500*1*x/100

=150x
c.i for 2nd year=(7500+150x)*1*x/100
= 7500+x^2

c.i-s.i=12

150x-7500+x^2=12

150x+x^2=12+7500

150x + x^2 =7512

x^2 + x=7512/150
=50.08

x=6.59....