A man sells a radio set for 34.50 and makes a profit of 15 percent. He sells a second radio set for 35.10 at a loss of 10 percent. If on the whole, he neither gains nor losses, find the cost price of the second radio set.

Let CP = cost price

Let SP = selling price

CP = (SP • 100)/(100 + given percent)

Is this the needed formula to solve this problem?