Answer:
1 donut and a bag of coffee costs $4.50
Step-by-step explanation:
Start by creating a pair of simultaneous equations.
Let a donut.
Let a bag of coffee.
Therefore:
There are a few ways to solve these equations. This time I'll show you the elimination method. We eliminate one of the variables to get the other variable equal to a number.
Start by multiplying one of the equations by a number so that one of the variables has the same coefficient (number at the front) as the same variable in the other equation.
I'll multiply the second equation by 2 so that the will have a coefficient of 2 like the 1st equation.
,
.
Now we have two equations with the same coefficient of . We can subtract the equations from each other to eliminate the
variable and leave
equal to a number.
Subtracting and
:
Simplify to get .
Therefore .
Now we have one of the variables, we can find the other variable by putting the known variable back into one of the equations.
- original equation
- substituting
.
- simplifying
- re-arranging to solve for
Therefore, and
.
So 1 donut costs $1.50 and 1 bag of coffee costs $3.
1 donut and a bag of coffee costs $4.50