Sundaram buys 40kg of wheat at rupees 6.25 per kg and 30kg of wheat at rupees 7 per kg. At what rate per kg should he sell the mixture to gain 5% on the whole?

Let us assume selling price to be Rs. x

CP of 40kg wheat at Rs. 6.25 per kg = 40 × 6.25

CP of 40kg wheat at Rs. 6.25 per kg = Rs. 250

CP of 30 kg wheat at Rs. 7per kg = 30 × 7

CP of 30 kg wheat at Rs. 7per kg = Rs. 210

Total CP = Rs. 460

Gain or loss = SP – CP

According to the question,

Selling price (x) = Rs. 483

per kg selling price

Per kg selling price

= Rs. 6.90 per kg

At Rs. 6.90 per kg should he sell the mixture to gain 5% on the whole.