Question

Whe cost of I pen = re and cost of 1 pencil box = y co 4 ( x+4 y=100 ) and ( (3 x)-(y)=15 ) o ( x+y=25 ) and ( y=3 x-15 ) o ( 0 x+3 x-15=25 Rightarrow 0 ) of ( x=10, y=15 )

# 11. The cost of 4 pens and 4 pencil boxes is 100. Three times the cost of a pen is 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 EXEMPLAR]

Solution