Question

cost of 3 pens is equal to that of 5 copies. what will be the cost for 25 copies if 9 pens and 7 copies cost Rs.264​

Answer 1

Answer:

Rs. 300

Step-by-step explanation:

We'll call the cost of pens $x$, and we'll call the cost of copies $y$.

We can write the simultaneous equations:

$\left \{ {{3x=5y} \atop {9x+7y=264}} \right.$

We'll times $3x=5y$ by 3 to get $9x=15y$.

Then we'll substitue this into $9x+7y=264$ to get

$15y+7y=264\\22y=264\\y=12$

So the cost of 25 copies will be

$12*25\\=300$(Rs)