Pg 520 (452) - Q17
You should draw the line out and label points X, R, S, T U, V, and
Y at the intervals 0, 1, 3, 6, 10, 13, and 25, respectively. If the
length of segment XY has to be less than 25 and greater than 13 (since
V is at 13), its midpoint m has to be so that 13 < 2m < 25.
In
other words, 2 times the midpoint has to be greater than 13 and
less than 25. V can’t be the midpoint because 2(13) = 26, which is
longer than the segment XY can be. T can’t be the midpoint either
because 2(6) = 12, which is shorter than point V at 13, and
the endpoint Y is after V. R and S pose the same problem.
The only possible midpoint of XY is U because 2(10) = 20, which is greater
than 13 and less than 25. So the
answer is D.