A grocer purchased 50kg salt at the rate of rs.8 per kg and mixed it wid 70kg salt purchased at the rate of rs 5 per kg .at what rate per kg must he sell the mixture to make a profit of 20% ?

I want sltn nd ans is rs 7.50per kg

To find the rate at which the grocer must sell the mixture to make a profit of 20%, we need to calculate the cost price and the selling price of the mixture.

Let's start by calculating the cost price of the mixture:

Cost of 50kg salt purchased at Rs. 8 per kg = 50 kg * Rs. 8/kg = Rs. 400
Cost of 70kg salt purchased at Rs. 5 per kg = 70 kg * Rs. 5/kg = Rs. 350

Total cost price of the mixture = Rs. 400 + Rs. 350 = Rs. 750

Now, let's calculate the selling price of the mixture with a profit of 20%:

Profit % = (Profit / Cost Price) * 100
Profit % = 20%

Profit = (Profit % / 100) * Cost Price
Profit = (20 / 100) * Rs. 750 = Rs. 150

Selling Price = Cost Price + Profit
Selling Price = Rs. 750 + Rs. 150 = Rs. 900

Finally, let's calculate the selling rate per kg:

Selling Rate per kg = Selling Price / Total weight of the mixture
Selling Rate per kg = Rs. 900 / (50 kg + 70 kg) = Rs. 900 / 120 kg = Rs. 7.50 per kg

Therefore, to make a profit of 20%, the grocer must sell the mixture at Rs. 7.50 per kg.