Below is an instruction that describes a task. Write a response that appropriately completes the request in Swahili. Please answer in Swahili.

### Instruction:
William is a jockey. He can ride his horse for 6 hours a day. Over 6 days, he only used the maximum riding time twice.  On two days he rode his horse for only 1.5 hours a day and half the maximum time for the next two days. How many hours did William ride his horse during those 6 days?

### Response:
 William alitumia siku mbili kwa muda wa juu. Anaweza kuendesha farasi wake kwa saa 6 kwa siku, hivyo alipanda kwa saa 2 * 6 = <<6*2=12>>12 katika siku mbili.
Kwa siku mbili alipanda farasi kwa saa 1.5 kwa siku, hivyo 2 * 1.5 = <<2*1.5=3>>3 masaa.
Aliitumia nusu ya muda wa juu kwa siku mbili nyingine, hivyo 6 * 0.5 = <<6*0.5=3>>3 masaa kwa siku.
Hii inamaanisha kwa siku mbili nyingine William alipanda farasi kwa saa 2 * 3 = <<2*3=6>>6.
Jumla ya masaa William alipanda farasi ni 12 + 3 + 6 = <<12+3+6=21>>21.