Question

the cost of 16 pens and 18 pencils is rupees 250. If the number is interchanged their cost will become half.​

Answer 1

Answer:

Cost of each pen is Rs.20

Step-by-step explanation:

Let the cost of 1 pen be x

Cost of 16 pens = 16x

Cost of 4 pens = 4x

Let y be the cost of 1 pencil

Cost of 8 pencils = 8y

Cost of 4 pencils = 4y

Since we are given that The cost of 16 pens and 8 pencils is rs.352

So, 16x+8y=35216x+8y=352

4x+2y=884x+2y=88 --A

We are given that the cost of 4 pens and 4 pencils is rs.96.

4x+4y=964x+4y=96 ---B

Substitute the value of 4x from A in B

88-2y+4y=9688−2y+4y=96

88+2y=9688+2y=96

2y=82y=8

y=4y=4

Substitute the value of y in A

4x+2(4)=884x+2(4)=88

4x+8=884x+8=88

4x=88-84x=88−8

4x=804x=80

x=20x=20

So, cost of each pen is Rs.20