Question

$3$ bags and $4$ pens together cost Rs. $257$, whereas $4$ bags and $3$ pens together cost Rs. $324$. Find the total cost of $1$ bag and $10$ pens.

Answer 1

Let the cost of 1 bag =$x$

And the cost of 1 pen =$y$

$\Rightarrow 3x+4y=257$

$\Rightarrow 4x+3y=324$

Equation (1) × $4$ : $12x+16y=257\times 4$

Equation (2) × $3$ : $12x+9y=324\times 3$

Subtract two equations ;

$\Rightarrow 7y=56$

$\Rightarrow y=8$

$\Rightarrow x=75$

$\Rightarrow$total cost of 1 bag and 10 pens$=x+10y=75+80=155$