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

### Instruction:
Wendy's truck has a gas tank that can hold 20 gallons. She also has a car with a gas tank that holds 12 gallons. The truck's tank is half full. The car's tank is 1/3 full. If she fills them both up completely, how many gallons does she add?

### Response:
 Tangi la lori lina galoni 10 kwa sababu 20 x .5 = <<20*.5=10>>10
Tangi la gari lina galoni 4 kwa sababu 12 x (1/3) = <<12*(1/3)=4>>4
Anahitaji kuongeza galoni 10 kwenye lori kwa sababu 20 - 10 = <<20-10=10>>10
Anahitaji kuongeza galoni 8 kwenye gari kwa sababu 12 - 4 = <<12-4=8>>8
Anahitaji kuongeza jumla ya galoni 18.