Question

If box+pen= 150gm pen+ pencil= 70gm 4boxes+3pens+pencil= 570gm Then, what os the weight of pencil?​

Answer 1

Step-by-step explanation:

let box be x , pen be y and pencil be z

therefore x+y=150-eqn1

4x+3y+z=570gm-eqn2

Eqn2 - 3*eqn1

4x+3y+z-3x-3y=570-450

x+z=120

Also pen + pencil=70

I. e. y+z=70---eqn3

adding all three equations gives you

x+y+z=170

subtracting eqn1

x+y+z-x-y=170-150

z=20gm

hence weight of pencil is 20gms