Question

hari and ajith borrowed rs. 8000 and rs. 6250 respectively at the same rate of interest fir 3 years if the hari paid an interest of Rs 735 more than Ajit. find the rate

Answer 1

let Ajit Paid interest is z
so, Hari paid interest is z+735

now,
for Ajit
SI =P x r x t /100
z = 6250 x r x 3 /100 ----------(1)

for Hari

SI = P x r x t/100
z+735 = 8000 x r x 3/100 ------------(2)

divide equation (1) and (2)
z/(z+735) = 6250/8000 =625 /800

z/(z+735) = 25/32

32 z =25 z +735 x 25

7z = 735 x 25

z= 105 x 25 = 2625 Rs

put z =2625 in equation (1)

2625 = 6250 x r x 3/100

r=26250/1875 = 14 %

hence rate is 14 %

Answer 2

let rate be x
principal taken by ajit=6250
time=3 years
SI=6250×3×x/100
=375x/2
principal taken by hari =8000
time=3 years
SI=8000×3×x/100=240x
ATQ
240x=375x/2+735
240x=375x+1470/2
240x(2)=375x+1470.
480x=375x+1470
480x-375x=1470
105x=1470
x=1470/105=14
therefore rate =14%