The Answer Is 500. 350 Is 70% Of 500.
The only thing that you need to do is Divide -2 on both sides to isolate the M. so 7/-2 M=3.5
Total number of cards = 13 + 5 + 2 = 20
Total number of yellow or green cards = 13 + 2 = 17
P(yellow or green) = 17/20
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Answer: 17/20