Question

a student bought some pens at 8 rupees each and some pencils at 1.50 rupees each.If the total number of pens and pencils purchased is 16 and their total cost is 50 rupees,how many pens did he buy?

Answer 1

Hey, check this

Let the number of pens = x

& number of pencils = y

x+y =16 ________(1)

8x + 1.5y = 50 __________(2)

Now, solve the above equations

Multiply eq (1) both by 8

8x +8y = 128

8x + 1.5y = 50

___________

- - -

6.5y = 78

→ y= 12

& put the value of y in eq (1)

x + y = 16

→ x = 4

pens = 4 & pencils = 16

Answer 2

Cost of pens = 8 rupees

Cost of pencils = 1.50 rupees

Total no. of pens and pencils purchased=16

Total cost=50rupees

So,no.of pencils = 1.50rupees ( 16-x )

Therefore,8x+24-1.50x=50

8x-1.50x = 50-24

6.50x = 26

x = 26÷6.50

x = 4

Therefore, 4 pens student buyed.