Question

The si of ` 600 for 4 yr and that of ` 600 for 2 yr together is ` 180.What is the rate of interest per annum?

Answer 1

P1= 600 P2=600

T1=4yrs T2=2yrs

R=r

SI1+S12= 180

S1 =x

x=600×4×r/100

SI2=180-SI1

= 180-x

=180-x=600×2×r/100

=180-600×4×r/100=600×2×r/100

=180-2400r/100=1200r/100

=180-24r=12r

=180=12r+24r

=180=36r

=r=180÷36

=r=5% p.a.