A city tower construction uses 4520 tones of cement trucked from a factory that is 7 kilometres
from the construction site. Each cement mixer can carry 7 tonnes of cement, and the cement
costs $85 per truck load for the first 30 loads and $55 per load after that.
a. How many loads of cement are needed? Add a full load for any remainder.
b. Find the total cost of cement needed to make concrete for the tower construction.