Thread: 2 more world problems (please help!!)

a) Two cement blocks and three bricks weigh 102lb, as do one cement block and ten bricks. What does one brick weigh?


b) A refrigerator repairman charges a fixed amount for a service call in addition to his hourly rate. If a two-hour repair costs $50 and a four-hour repair costs $74, what is the repairman's hourly rate?

Originally Posted by pinkmath135

a) Two cement blocks and three bricks weigh 102lb, as do one cement block and ten bricks. What does one brick weigh?

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?

b) A refrigerator repairman charges a fixed amount for a service call in addition to his hourly rate. If a two-hour repair costs $50 and a four-hour repair costs $74, what is the repairman's hourly rate?

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?

Originally Posted by Jhevon

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?

need more explaining please.