Let

be the weight of a cement block

Let

be the weight of a brick

then we have the system:

....................(1)

....................(2)

solve this system for

and you will have your answer. can you continue?

Let

be the hourly rate

Let

be the number of hours the repair takes

Let

be the fixed charge.

then the cost of the repair is given by:

since a two hour repair costs $50, we have:

..................(1)

since a four-hour repair costs $74, we have:

...................(2)

thus we need to solve the following system

..................(1)

..................(2)

for

can you continue?