Question

A grocery dealer cheats to the extent of 10% while buying
as well as selling by using false weight. What is his increase
in the profit?
(a) 20%
(b) 21%
(c) 22
(d) None of these



full explain​

Answer 1

Given:

A grocery dealer cheats to the extent of 10% while buying  as well as selling by using false weight.

To find:

What is his increase  in the profit?

Solution:

We use the formula: (a + b + ab/100) %

From given, we have,

A grocery dealer cheats to the extent of 10% while buying  

A grocery dealer cheats to the extent of 10% while selling  

= (a + b + ab/100) %

= (10 + 10 + 10×10/100) %

= (20 + 1) %

= 21 %

Therefore, option (b) is correct.

Answer 2

Given :

A grocery dealer cheats to the extent of 10% while buying  as well as selling by using false weight

To Find :

The increase in profit percentage

Solution :

Let The true value of grocery = 100 grams

As The error percentage = 10 %

So, The error percentage of grocery = 10% + 10% + $\dfrac{10\times 10}{100}$ %

                                                             = 21 %

Or, The error value of grocery = 100 gm + 21 % of 100 gm

                                                  = 100 gm + $\dfrac{21}{100}$ × 100 gm

                                                  = 121 gm

Now,

Profit% = $\dfrac{Error value - original value}{original value}$ × 100

         = $\dfrac{121 gm-100gm}{ 100 gm}$ × 100

         =  $\dfrac{21 gm}{100 gm}$ × 100

         = 21

i.e profit = 21 %

Hence, The increase in profit of dishonest grocery dealer is 21 %  Answer