A problem like this is best solved with a system of equations. We have two unknown pieces of information we need:
1) How much a chair costs to rent
2) How much a table costs to rent
What we do know is two different total costs for combinations of renting chairs and tables. We can turn those costs and combos into equation formats. We have 2 unknown variables, so we will need two equations to be able to solve for both.
Start by identifying two separate variables for a chair and a table:
Let x be chairs
Let y be tables
Now we'll look at the cost combinations we were given:
For the first combo:
5 chairs and 2 tables rented add to $26.
In equation form:
5x + 2y = 26 (Equation 1)
For the second combo:
3 chairs and 8 tables add to $87.
In equation form:
3x + 8y = 87 (Equation 2)
Using substitution, try and solve for x or y in either equation 1 or 2 first. This will give you what x equals in terms of y, or what y equals in terms of x. Then plug that value into the other equation you did not use first to solve for a numerical value you can use to find the other one you need.
I'll give an example:
Solve for x first using equation 1:
5x + 2y = 26
5x = 26 - 2y
x = (1/5) * (26 - 2y)
Now we'll put that value of x wherever there is an x in equation 2:
3x + 8y = 87
3 * (1/5) * (26 - 2y) + 8y = 87
Once you solve using distribution and factoring, you should find that y = 10.5. When you plug this back into the first equation used in this example, equation 1, you will also find that x = 1.
Remember to identify which value is which in your answer with proper units and any additional symbols.
In that case:
x = the cost to rent per chair
y = the cost to rent per table
We were given dollars as our unit to use, so unless a problem asks for a different unit, assume that you should use the same unit that was originally given to you in the problem.
Therefore,
it costs $1 per chair
it costs $10.50 per table
Hope this helps!
