Answer:

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Work Shown:

You could expand terms out and simplify, but I think it's more handy to leave it in this form so you can easily spot the center and radius from a glance.
Answer:
Jose had 60 cards
Phillipe had 15 cards
Step-by-step explanation:
Let the number of trading cards Phillipe had be x. Jose had 4 times, meaning he has 4x of these cards.
Jose gave away 50 cards while Phillipe gave away 5 cards to make their numbers equal.
Mathematically:
4x - 50 = x - 5
3x = 45
x = 45/3 = 15
Phillipe had 15 cards while Jose had 15(4) = 60 cards
Approximately 68% of a normal distribution lies within one standard deviation of the mean, so this corresponds to students with scores between

.
The answer would be (A) 6