Question

The cost of a pencil is 25 cents.more than the cost of a eraser. If the costs of 8 pencils and 10 erasers is $12.80,find the cost of each.

Answer 1

let the cost of eraser is x
cost of a pencil is 25% more than it
so cost of a pencil is x+x*25/100=5x/4
now cost of 8 pencils is 8*5x/4= 10x rs
and cost of 10 erasers is 10*x= 10x rs
so, 10x+10x=12.80
or 20x= 12.80
or x= 0.64
and 5x/4= 0.8
so cost of a eraser 0.64 rs
cost of a pencil 0.80 rs

Answer 2

Answer:

Cost of an Eraser=x=60

Cost of a pencil=25+x=85

Step-by-step explanation:

Pencil

25+x  

Eraser

x

8(25+x)+10x=1280. [1 dollars = 100 cents]

[12.80 dollars=1280 cents]

=200+8x+10x=1280

=200+18x=1280

=18x=1280-200

=18x=1080

x=1080÷18

x=60

Cost of an Eraser=x=60

Cost of a pencil=25+x=85