The price of each type of beans is such that it is impossible to create a mixture which price is higher than highest ingredient price. In this case we have one type of bean that costs $0.72 and one that cost $0.52 per pound. Even if the mixture is made purely out of first type of beans it wouldn't cost $0.74 per pound.
In general, you solve this problem using this system of equations:
x + y = 110
x0.72 + y0.52 = 0.74 * 100