Dafina E. answered 11/17/16
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Set the cost of a small box of tangerines = x and the cost of a large box of tangerines = y
Danielle sold 3 small boxes and 4 large boxes for a total cost of $103. Therefore,
3x + 4y = 103
(the cost of 3 small boxes plus the cost of 4 large boxes equals $103)
Chelsea sold 6 small boxes and 7 large boxes totaling $187. Therefore,
6x + 7y = 187
(the cost of 6 small boxes plus the cost of 7 large boxes equals $187)
Now you have two equations and 2 unknowns, so you can solve for x and y
3x + 4y = 103
6x + 7y = 187
Using the elimination method, multiply the top equation by 2
2 (3x + 4y = 103) → 6x + 8y = 206
Then subtract the two equations
6x + 8y = 206
- 6x + 7y = 187
0x + y = 19
Now that you know y = 19, you can substitute that into one of the two original equations.
Substituting y = 19 into the first equation give you
3x + 4(19) = 103
3x + 76 = 103
3x = 27
x = 9
Final Answer:
The small boxes of tangerines, x, cost $9.
The large boxes of tangerines, y, cost $19.