Answer:
D 41/10
Step-by-step explanation:
substitute the values given into the equation. Calculate.
Let C be the amount of compost
T be the amount of topsoil
Each compost cost = $25
Cost of C compost = 25C
Each topsoil cost = $15
Cost of T topsoil = 15T
Amount of compost + amount of topsoil = 10
C + T = 10 -------> Equation 1
cost of C compost + cost of T topsoil = 180
25C + 15T = 180 --------> equation 2
Solve the first equation for C
C + T = 10
C = 10 - T
Now plug it in second equation
25C + 15T = 180
25 ( 10 - T) +15T = 180
250 - 25T + 15T = 180 (combine like terms)
250 - 10 T = 180 (Subtract 250 on both sides)
-10T = 180 - 250
-10T = -70 ( divide by -10 on both sides)
T = 7
She purchased 7 cubic yards of topsoil .
The plus sign means that we have to sum all the terms inside of the second parenthesis, while the minus sign means that we have to change all the signs inside the last parenthesis:
Now we only have to gather all like terms:
