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

### Instruction:
A family went out to see a movie. The regular ticket costs $9 and the ticket for children is $2 less. They gave the cashier two $20 bills and they received a $1 change. How many children are there if there are 2 adults in the family?

### Response:
 Familia ililipa $40 kwa sababu 2 x $20 = $<<2*20=40>>40.
Walipokea pesa ya $1 kama mabadiliko, hivyo tiketi zao ziligharimu $9 - $1 = $<<9-1=8>>8.
Tiketi za watoto zinagharimu $9 - $2 = $<<9-2=7>>7.
Tiketi za watu wazima zinagharimu $8 x 2 = $<<8*2=16>>16.
Tiketi za watoto zinagharimu $7 x 2 = $<<7*2=14>>14.
Familia ililipa jumla ya $16 + $14 = $<<16+14=30>>30.
Kuna watoto 2 + 1 = <<2+1=3>>3.