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

### Instruction:
There were 18 students assigned in a minibus for a field trip. Eight of these students were boys. On the day of the field trip, the number of girls and boys was the same since some of the girls were not able to join the trip. How many girls were not able to join the field trip?

### Response:
 Kulikuwa na wavulana 8 hivyo kulikuwa na wasichana 18 - 8 = <<18-8=10>>10.
Kwa kuwa idadi ya wasichana na wavulana ilikuwa sawa siku ya safari ya kimasomo, basi kulikuwa na wanafunzi 8 + 10 = <<8+10=18>>18.
Hivyo, 10 - 8 = <<10-8=2>>2 wasichana hawakuweza kujiunga na safari ya kimasomo.