
When

,

Meanwhile, you have on the right

so the equality holds for

.
Assume it holds for

, i.e. that

Now for

, you have






as required.
if you convert it all into one hour, Team B clearly worked at a faster pace.
To approximate the distance of points with three dimension, make use of the equation,
d = sqrt ((x2 - x1)^2 + (y2 - y1)^2 +(z2 - z1)^2)
Substituting all the data from the points given,
<span>d = sqrt ((2 - -2)^2 + (-7 - 3)^2 +(4 - -5)^2) = sqrt 197
</span>
Thus, the distance from the points is approximately 14.04 and that is letter D.