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

### Instruction:
 Rubble ana $15 mfukoni mwake na anahitaji kununua madaftari 2 na kalamu 2. Kila daftari lina gharama ya $4.00 wakati kila kalamu ina gharama ya $1.50. Rubble atabakiwa na pesa ngapi baada ya manunuzi?


### Response:
 Gharama ya jumla ya madaftari 2 ni $4.00 x 2 = $<<4*2=8.00>>8.00.
Gharama ya jumla ya kalamu 2 ni $1.50 x 2 = $<<1.5*2=3.00>>3.00.
Jumla ya pesa ambazo Rubble ametumia kwa vitu vyote ni $8.00 + $3.00 = $<<8+3=11>>11.00.
Hivyo jumla ya pesa iliyobaki kwa Rubble ni $15.00 - $11.00 = $<<15-11=4>>4.00.