context: ###List of Questions
  (1) In base 16, what is 2 - -15?
  (2) Let r = 1/6632 - -401227/59688. Find the common denominator of r and 77/8.
  (3) Four letters picked without replacement from gttggt. What is prob of sequence gtgt?
  (4) How many meters are there in 67/5 of a kilometer?
  (5) Let y = -2 - -2. Let a be (-1 - 0)*y/1. Solve -4 = -2*t - a*t for t.
q_1: (1) In base 16, what is 2 - -15?
q_2: (2) Let r = 1/6632 - -401227/59688. Find the common denominator of r and 77/8.
q_3: (3) Four letters picked without replacement from gttggt. What is prob of sequence gtgt?
q_4: (4) How many meters are there in 67/5 of a kilometer?
q_5: (5) Let y = -2 - -2. Let a be (-1 - 0)*y/1. Solve -4 = -2*t - a*t for t.