Hi there! Hopefully this helps!
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It decreased by 30 cents per week.
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The average rate of change is calculated as:
the ratio of the sum of the change in the three weeks divided by the number of weeks. (The number of weeks being 3)
Rate of change =
.
(-60 + -10 + -20 = -90). So, to simplify it:
= -30
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Incase you are confused:
Since the average rate of change is negative, this means that the stock price has decreased.