After a mark-up of #40%# was added to an item a boy sells it for #Rs.35#. What was his cost price and how much was his mark-up?

1 Answer
Dec 12, 2016

The cost price is Rs.25 and the markup is Rs.10.

Explanation:

The important thing to note here is that you cannot just find 40% of Rs.35 and subtract it.

The boy's cost price represents 100%, onto which 40% is added to give Rs.35.

Therefore Rs.35 represents #140%# of the cost price and we need to find the value of the 100% and the 40%.

Using
direct proportion:

#35/140 = x/100#

#x = (35xx100)/140#

#x = 25" "larr# this is the cost price.

#35-25 = 10" "larr# this is the mark up

Make an equation Let the cost price be #p#

#140% xx p = 35#

#140/100 xx p= 35#

#p = 35 xx 100/140#

#p = 25#