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?

1 Answer
May 19, 2018

Answer:

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#