Question

Cost of 2 pens and 5pencils is ₹100. Cost of 5pens and 7pencils are cost ₹150 ,then find the cost of 4pens and 5pencils.​

Answer 1

Step-by-step explanation:

Let's take the cost of a pen be x ruppees and cost of a pencil be y ruppees. 2x+5y=Rs.100 (1) and 5x+7y=Rs. 150 (2). Multiply (1) by 5

2x+5y=100 =>5(2x+5y)=5(100)=500 =

10x+25y =500. Multiply (2) by 2. 2(5x+7y)=2(150) =>10x+14y=300. Now subtract (1) from (2) =>10x+25y-(10x+14y) = 500-300=>11y=200=>y=200/11 ruppees. Substitute y=200/11 in equation(1) => 2x+5(200/11) = 100 => 2x= 100 -1000/11 =>2x =(1100-1000)/11 =>2x=100/11 =>x=50/11 ruppees. So the cost of a pen is 18.18 ruppees and the cost of a pencil is 4.54 ruppees approximately. Hope it helps you.