Question

raju went to the market to purchase three pens.the cost of first pen was more than that of the second by 25%,whoch was more than that of the third by 20%.If the average cost of the first two pens was 15/- more than that of the last two pens.Find the cost of the costliest pen.​

Answer 1

if a is more than b by 25%, then a=1.25b

[ a=b+(25%)b=1.25b]

let cost of first pen,second and third pen be x,y,z respectively..

Given first pen is 25% more than second pen,

x=1.25y

second pen is 20% more than third pen,

y=1.2z

average cost of 1st and 2nd pen is 15 more than avg cost of 2nd and 3rd pens

(x+y)/2=15+(y+z)/2

solving we get x-z=30-----(1)

write x in terms of 'z'

x=1.25y

x=(1.25)(1.2z)

x=1.5z------------(2)

using eq(1) and (2)

we get z=60/-

hence y=1.2z=72/-

x=1.25y=90/-