Question

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

Answer 1

Total cost = Rs 50

Pen = Rs 8

Pencil = Rs 1.50

Total pen and pencils bought = 16

.

Assumed he bought all pencils:

Total cost = 16 x 1.5 = Rs 24

.

Find difference in cost:

50 - 24 = 26

.

Find difference in cost of pen and pencil:

8 - 1.5 = Rs 6.5

.

Find number of pens:

26 ÷ 6.5 = 4

.

Find the number of pencils:

16 - 4 = 12

.

Answer: The student bought 12 pencils and 4 pens.

Answer 2

Step-by-step explanation:

Let the number of pens be x and

number of pencils be y

then

x+y=16ory=16−x

andtheirvalue

8x+1.5y=50

8x+(  2+3 )(16−x)=50

8x+24−(  2 3  )x=50 8x−(  2 3

​   )x=50−24 (  2 13x

​   )=26∴x=4 then y=16−x=16−4=12