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

### Instruction:
John climbs 3 staircases.  The first staircase has 20 steps.  The next has twice as many steps as the first.  The final staircase has 10 fewer steps than the second one.  Each step is 0.5 feet.  How many feet did he climb?

### Response:
 Ngazi ya pili ilikuwa na hatua 20*2=<<20*2=40>>40
Ngazi ya mwisho ilikuwa na hatua 40-10=30
Jumla ya hatua alizokwea ni 20+40+30=<<20+40+30=90>>90
Hivyo, alikwea futi 90*.5=<<90*.5=45>>45