A shopkeeper buys two types of tea one at $20 for 10 kg and the other at $23 for 10 kg. He mixes the two types and the mixture is sold at $38 for 10 kg. What will be his percentage profit?

Let us take the case of first type of tea

Cost of 10 kg of tea one = $20

Then

Cost of 1 kg of tea one = (20/10) dollars

= 2 dollars

Now let us take the case of the second kind of tea

Cost of 10 kg of tea = $23

Then

Cost of 1 kg of tea = (23/10) dollars

= 2.3 dollars

So

The mixture of 1 kg of tea one

and 1 kg of second type of tea will cost = (2.0 + 2.3) dollars

= 4.3 dollars

Then the cost of 2kg mixture of tea costs = 4.3 dollars

So

The cost of 10 kg mixture will cost = (4.3/2) * 10 dollars

= 4.3 * 5 dollars

= 21.5 dollars

Then

The amount of profit made by selling 10 kg tea at $38 = (38 - 21.5) dollars

= 16.5 dollars

So

Percentage of profit made = (16.5/21.5) * 100

= 1650/21.5

= 76.74 percent

So the percentage of profit made is 76.74%.