Question

. 5 pens and 1 book together cost Rs. 225. Cost of 10 pens is equal to the cost of 1 book. Find the total cost of 3 pens and 2 books.

Answer 1

by given
let pens be x
book be y
so
5x+y=225
y=10x
so
5x+10x=225
15x=225
x=15
and 1 book=10x=150
so,
3 pens=3×15=45
2books=2×150=300
total cost=300+45=345 ans

Answer 2

5 pens and 1 book together cost Rs. 225.

cost of 10 pens = cost of 1 book

so..

cost of 5 pens + 10 pens = Rs 225

cost of 15 pens = 225

cost of each pen = 225 /15 = 15

then cost of 1 book = cost of 10 pens= 10×15 =150

then cost of 3 pens and 2 books = 3(10) + 2(150) = 30 + 300 = 330