Question

1) 3 books and 10 pens together cast Rs.300.2 books and 3 pens together cost Rs. 145. Find
the cost of l book and 3 pens.​

Answer 1

Answer:

Let the cost of 1 book =x

And the cost of 1 pen =y

⇒5x+7y=79

⇒7x+5y=77

Equation (1) × 7 : 35x+49y=79×7

Equation (2) × 5 : 35x+25y=77×5

Subtract two equations ;

⇒24y=168

⇒y=7

⇒x=6

Total cost of 1 book and 2 pens =x+2y=6+14=20