Question

Jade invested in the stock market. The weekly change in the value of her stock, in dollars, over 4 weeks was +23.65, -22.20, -12.75, and +5.98. What is the average weekly change in the value of her stock, in dollars?

Answer 1

There is a trap in this question.

mean change `=(-45.85+9.45+18.73)/3= -5.89`

Explanation:

There are 3 types of average; mean, median and mode. I am assuming you intend the mean to be used.

A mean is that single value which if it is multiplied by the total count of related values it give the same answer as the sum of those related values.

`color(brown)("This part is the trap in the question")`

The sum `->23.65-22.20-12.75+5.98 = -5.32`

Count `->4`

Mean `->-5.32/4=1.33`
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
`color(brown)("Read the question again. This is what it is asking for")`

`color(green)("What is the average weekly "color(red)("change")" in value")`

`color(blue)("First change ")->+23.65 -(-22.20) = 45.85`
`color(white)("dddddddddddddd")`but it decreased so the change is negative.

`color(white)("dddddddddddddd")color(blue)(-45.85)`.
...........................................................................................
`color(blue)(S"econd change")-> -22.20-(-12.75)=-9.45`

`color(white)("ddddddddddddddd")`but `-12.75 > -22.20` so it increased
`color(white)("ddddddddddddddd")`thus the change is positive

`color(white)("ddddddddddddddd")color(blue)(+9.45)`
...................................................................................................
`color(blue)("Third change") -> -12.75-(+5.98)=-18.73`
`color(white)("dddddddddddddd")`but it increased thus the change is positive.

`color(white)("dddddddddddddd")color(blue)(+18.73)`
.................................................................................................

`color(blue)("Putting it all together")`

mean change `=(-45.85+9.45+18.73)/3= -5.89`