Question

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

Answer 1

‘Cost price’ of a ‘pencil’ is Rs.12.

Given:  

A dozen of pencil is sold at a profit of 15% where the selling price is Rs. 13.80

To find:  

The ‘cost price’ of a pencil

Solution:  

Let us assume that cost price of pencils is ‘a’

Now at 15% profit, selling price is Rs.13.80

Now profit is calculated on cost price.

Hence, the profit will be 0.15a

We know that, Selling price = Cost price + Profit

13.80 = a + 0.15a (Replacing cost price as a and profit as 0.15a)

13.80 = 1.15a

$a=\frac{13.80}{1.15}$

a = 12

Hence, the cost price of pencils = Rs.12  

Answer 2

Answer:

Cost price of 1 pencil = Rs 1

Step-by-step explanation:

Given , selling price of dozen pencils (s.p) = Rs 13.80

Profit (g) = 15%,

cost price of dozen pencils = ?

$cost \:price = \frac{s.p\times 100}{100+g}\\=\frac{13.80\times 100}{100+15}\\=\frac{1380}{115}\\=12$

Now,

Cost price of 12 (dozen) pencils = Rs 12

Cost price of 1 pencil = 12/12= Rs 1

Therefore,.

Cost price of 1 pencil = Rs 1

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