question: Chase and Rider can ride their bikes thrice a day for 5 days; but on two other days, they ride twice the times they do on usual days. How many times do they ride their bikes a week?
answer: Each person rides his bike 3 x 5 = <<3*5=15>>15 times for 5 days.
  Together, they ride 15+15 = <<15+15=30>>30 times for five days.
  Each person rides his bike 3 x 2 = <<3*2=6>>6 times for every day of the other two days.
  This means each person rides 6*2 = <<6*2=12>>12 times on each day of the other two days.
  The total for the other two days is 12+12 = <<12+12=24>>24
  For the whole week the together ride 24+30 = <<24+30=54>>54 times
  #### 54