Question

A milkman purchases milk at the rate of rs. 14 per litre and then mixes 40% water to it. Find the profit per cent, if he sells the mixture at Rs. 6 per litre.

Answer 1

Let the quantity of milk purchased be x litres.
C.P. of 1 litre = Rs.14
∴ C.P. of x litre = Rs.14x
Quantity of water mixed
= 40% of x = `(40)/(100)x`
= `(2)/(5)x  "litres"`
∴ Quantity of milk now becomes 
= `x + (2)/(5)x`
= `(7)/(5) x  "litres"`
S.P. of 1 litre mixture = Rs.16
∴ S.P. of `(7)/(5)x` litres mixture
= `16.(7)/(5)x`

= Rs.`(112)/(5)x`
Profit = S.P. - C.P.
= `(112)/(5)x - 14x`

= `(112x - 70x)/(5)`

= `(42)/(5)x`
Profit %
= `"Profit"/"C.P." xx 100`

= `((42x)/(5))/(14x) xx 100`
= 60%.