14 . B
Plug and b = t^2 into the expression:
15 . C
Each point is connected to five other points to make 5 chords per point. But this counts
every chord twice—AB is indistinguishable from BA—so after you multiply 6 by 5, you have to
divide by 2, yielding 15.
16 . B
Take the computers one at a time. Put everything in terms of seconds: t minutes is 60t
seconds and s minutes is 60s seconds.
The new computer performs calculations per second, which is calculations in t
minutes. The old computer performs calculations per second, which is
calculations in t minutes.
The number of calculations they perform together is
17 . D
Try the two given points in the choices. The point (−3,0) satisfies (B) and (D). The point (2,0)
satisfies (A) and (D). The only choice that works both times is (D).
18 . C
You want to rank a, b, and c. Actually, because you’re given three equations, you can solve
for the three unknowns. Subtract the equation b + c = 10 from the equation a + b = 15, and
you get a − c = 5. Now add that to the equation a + c = 13, and you get 2 a = 18, or a = 9. Now