Question

A mobile vendor has 22 items, some which are pencils and others are ball pens. On a particular day, he is able to sell the pencils and ball pens. Pencils are sold for ₹ 15 each and ball pens are sold at ₹ 20 each. If the total sale amount with the vendor is ₹ 380, how many pencils did he sell?

Answer 1

Let vendor have ‘p’ number of pencils & ‘b’ number of ball pens

Given that total number of items is 22

∴ p + b = 22

Pencils are sold for ₹ 15 each & ball pens for ₹ 20 each

total sale amount = 15 x p + 20 x b

= 15p + 20b which is given to be 380.

∴ 15p + 20b = 380

Dividing by 5 throughout,

15p/5 + 20b/5 = 380/5

⇒ 3p + 4b = 76

Multiplying equation (1) by 3 we get

3 x 7 + 3 x b = 22 x 3

⇒ 3p + 3b = 66

Equation (2) – (3) gives

∴ b = 10

∴ p = 12

He sold 12 pencils