Answer:
F. w > 12.6, minimum of 13 weeks
Step-by-step explanation:
The amount Jachin will have in his savings account will be the sum of the initial amount and the product of the weekly deposit and the number of weeks. Jachin wants that amount to be more than $400. The inequality that represents Jachin's desired bank balance is ...
85 +25w > 400 . . . . . initial balance plus deposits total more than $400
25w > 315 . . . . . . . subtract 85
w > 12.6 . . . . . . . divide by 25; solution to the inequality
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Jachin makes a deposit once a week, so the value of w will be an integer. The requirement that the value of w be greater than 12.6 means it will take at least 13 weeks for Jachin to save more than $400.
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Additional comment
We don't know how much more than $400 Jachin needs to save. We only know it is some amount more than $400. Hence, we cannot say that after week 13 when Jachin has a balance of $410 that he can buy the tablet. This means the "no more than ..." answer choices have no basis in the problem statement and must be ignored.
This only leaves the first and last answer choices as being worthy of consideration. The first choice presumes that w may take on a non-integer value. If Jachin makes a deposit once a week, he will not be making a deposit when w = 12.6 weeks. He will be making his deposit when w = 13 weeks.
