Answers:
3 chocolate cones
1 strawberry cones
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Explanation:
Let's isolate the variable c in the first equation
c+s = 4
c = 4-s
we subtract s from both sides to get c all by itself. This will then be plugged into the second equation. I'm using the substitution property.
1.75c + 1.3s = 6.55
1.75(4-s) + 1.3s = 6.55 ..... replace c with 4-s
1.75*4 + 1.75*(-s) + 1.3s = 6.55
7 - 1.75s + 1.3s = 6.55
-0.45s + 7 = 6.55
-0.45s = 6.55 - 7
-0.45s = -0.45
s = -0.45/(-0.45)
s = 1
So he bought 1 strawberry cone. Use this value of s to find c
c = 4-s
c = 4-1
c = 3
This says he also bought 3 chocolate cones.
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As a check, we see that c+s = 3+1 = 4, showing that he bought 4 cones total.
Also,
1.75c + 1.3s = 1.75*3 + 1.3*1 = 6.55
indicating he spent $6.55 total for the four cones. This matches with what the instructions tell us, so the answer is confirmed.
