context: ###List of Questions
  (1) Calculate 0.4*142.5.
  (2) What is the remainder when 51 is divided by 460/36 + (-4)/(-18)?
  (3) Two letters picked without replacement from {r: 3, l: 6, j: 6, u: 3}. What is prob of picking 1 u and 1 r?
  (4) How many minutes are there in 1/6 of a hour?
  (5) Solve 29 = 5*c - 3*k, -9 = -4*c + 4*k + 19 for c.
q_1: (1) Calculate 0.4*142.5.
q_2: (2) What is the remainder when 51 is divided by 460/36 + (-4)/(-18)?
q_3: (3) Two letters picked without replacement from {r: 3, l: 6, j: 6, u: 3}. What is prob of picking 1 u and 1 r?
q_4: (4) How many minutes are there in 1/6 of a hour?
q_5: (5) Solve 29 = 5*c - 3*k, -9 = -4*c + 4*k + 19 for c.