Question

if 7 pens cost rupees 4.20 what is the cost of 3 pens

Answer 1

Cost of 7 pens = Rs 4.20

Cost of 1 pen = 4.20/7 = 0.6

Now , Cost of 3 pens = 0.6×3 = Rs 1.8

Three pens cost Rs1.8 .

Here we use unitary method.

In that method First we have to find the cost of 1 then multiply by the required.

Thanks !!

Answer 2

No.of pens= 7

cost of 7 pens = 4.20

Then the cost of each pen will be

= cost of pens/no.of pens

=Rs 4.20/7

= Rs 0.6 or 60 paise


The cost of 3 pens will be..

=No.of pens × cost of each pen

=3 × 0.6

= Rs 1.8