The cost of 4 pens and 4 pencil boxes is Rs 100. Three times the cost of a pen is Rs 15 more than the cost of a pencil box. Form the pair of linear equations for the above situation. Find the cost of a pen and a pencil box

NCERT Class X
Mathematics - Exemplar Problems

Chapter _PAIR OF LINEAR EQUATIONS IN TWO VARIABLES

1

Answers

  • Brainly User
2015-06-10T20:19:46+05:30
Let price of pens be =x
let price of pencil boxes =y
4x + 4y = 100 ----- 1
3x- y=15 ------- 2
x=100-4y/4 
putting value of x in 2
3(100-4y/4) - y =15
300 - 12y/4 -4 =15
300- 12y-4y = 60
300 -16y =60 
-16y = -240
y= -240/-16=15
0