Answer: She purchased 72 cones, 32 balls, and 60 vests.
Step-by-step explanation:
The total number of items is 164.
The price of the vests is $2.50 each.
The price of the soccer balls is $9.25 each.
The price of the cones is $0.75 each.
The total budget was $500.
If V is the number of vests, B the number of balls, and C the number of cones, we have that:
V + B + C = 164.
V*$2.50 + B*$9.25 + C*$0.75 = $500.
and:
"She purchased 40 more cones than balls."
C = B + 40.
Then we have a system of 3 equations and 3 variables:
V + B + C = 164.
V*$2.50 + B*$9.25 + C*$0.75 = $500.
C = B + 40.
Here the first step is to replace the third equation into the other two, in this way we eliminate one variable and one equation:
V + B + (B + 40) = 164
V*$2.50 + B*$9.25 + (B + 40)*$0.75 = $500.
Now we want to isolate one variable in one of the equations, i will isolate V in the first equation:
V = 164 - 2*B - 40 = 124 - 2*B
Now i can replace this into the other equation:
(124 - 2*B)*$2.50 + B*$9.25 + (B + 40)*$0.75 = $500
Now let's solve this for B.
$310 - $5*B + B*$9.25 + B*$0.75 + $30 = $500
B*( $9.25 - $5 + $0.75) = $500 - $310 - $30
B*$5 = $160
B = 160/5 = 32
Now we know the value of B.
And by the equations above:
V = 124 -2*B = 124 - 2*32 = 60
C = B + 40 = 32 + 40 = 72.
Then:
She purchased 72 cones, 32 balls and 60 vests.
