Question

If at 15%profit,the selling price of a dozen pencil is rs.13.80;then what is the cost price of a pencil

Answer 1

11.73/12=.085 should be there

Answer 2

The Cost price of 1 pencil is Rs.1

Explanation:

Given:

1. The selling price of a dozen pencils is rs.13.80

2. Profit% = 15%

To find:

The cost price of the pencil

Formula:

Profit = Selling Price - Cost Price

Loss = Cost Price - Selling Price

Profit% = $\frac{Profit}{CP} \times100$

Loss% = $\frac{Loss}{CP} \times100$

Solution:

==> SP of  dozen pencil = Rs.13.80

==> 1 dozen = 12 pencil

==> 12 pencil = Rs.13.80

==> Profit % = 15

==> Profit% = $\frac{Profit}{CP} \times100$

==> Profit = SP-CP

==> Profit% = $\frac{SP-CP}{CP} \times100$

==> Profit% = $\frac{SP}{CP} -\frac{CP}{CP} \times100$

==> Profit% = $\frac{SP}{CP}-1 \times100$

==> $\frac{15}{100}=\frac{SP}{CP}-1$

==> 0.15 =                  $\frac{SP}{CP}-1$

==> $0.15+1 = \frac{SP}{CP}$

==> 1.15×CP = SP

==> SP=  Rs.13.80

==> $CP=\frac{13.80}{1.15}$

==> CP = Rs.12

==> Cost Price of 12 pencils is Rs.12

==> 1 dozen = 12 Pencils

==> CP= 12 Pencils = Rs.12

==> Divide by 12 on both sides

==> 12/12  Pencils =Rs. 12/12

==> 1 pencil = Rs.1

==> The Cost price of 1 pencil is Rs.1