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

### Instruction:
Darnell pays $12 for unlimited texting and calling on his phone each month. An alternative phone plan would charge $1 per 30 texts and $3 per 20 minutes of calls per month. Darnell sends 60 texts and spends 60 minutes on the phone each month. How many dollars less would he pay on the alternative plan?

### Response:
 Darnell atalipa 60 / 30 = <<60/30=2>>2 mara ya kiwango cha ujumbe cha $1 kila mwezi.
Atalipa 60 / 20 = <<60/20=3>>3 mara ya kiwango cha dakika cha $3 kila mwezi.
Atalipa 2 * 1 + 3 * 3 = 2 + 9 = 11 dola kwa mwezi kwenye mpango mbadala.
Hivyo, Darnell atalipa $12 - $11 = <<12-11=1>>1 kidogo kwenye mpango mbadala.