Check your answer by confirming that the price you found max

Check your answer by confirming that the price you found maximizes the revenue for the given information.

Solution: given first day ticket price is 10.5 doller and 1400 ticket sold

and per day .5 doller inc. price and 40 less sold

then the revenue of the day is (10.5+.5x)(1400-40x) where x is no. of the day

diffrentiet the eq., we get x=7

7 th day revenue is maximum

A(x)=(10.5+.5x)(1400-40x)