Question

The table below shows the high temperature, in degrees Fahrenheit, each day in Fairbanks, Alaska, during a week in January. Day: Sunday High temp: -8 Day: Monday High temp: 2 Day: Tuesday High temp: -6 Day:Wednesday High temp: -3 Day Thursday High temp: 4 Day: Friday High temp:5 Day Saturday High temp:-1The following sunday, Erin recorderd the High tenperature and then calculated the mean high temperature, which she found was -1.5 F. What was the temperature on Sunday?

Answer 1

Let y be the temperature

$\operatorname{mean}=\frac{\Sigma x}{n}$

mean =-1.5

n=8

substitute in the above

$-1.5=\frac{-8+2+(-6)+(-3)+4+5+(-1)+y}{8}$$-1.5=\frac{-7+y}{8}$

Multiply both-side of the equation by 8

$-1.5(8)=-7+y$$-12=-7+y$

Add 7 to both-side of the equation

$-12+7=y$$-5=y$$y=-5$