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

### Instruction:
Colbert is building a treehouse out of wooden planks. The treehouse needs 200 wooden planks. A quarter of these planks come from Colbert’s storage, half of these planks come from Colbert’s parents, 20 planks come from Colbert’s friends and he buys the rest from the store. How many planks of wood does he need to buy from the store to finish his treehouse?

### Response:
 Kwenye ghala la Colbert, kuna mbao 200 / 4 = <<200/4=50>>50.
Kwenye ghala la wazazi wa Colbert, kuna mbao 200 / 2 = <<200/2=100>>100.
Hivyo, jumla ya mbao ambazo Colbert hajalazimika kununua ni mbao 50 kutoka ghala + mbao 100 kutoka kwa wazazi = mbao 150.
Pia, anapokea mbao 20 kutoka kwa marafiki zake, ambayo inamaanisha bado anahitaji kununua mbao 200 - 150 - 20 = <<200-150-20=30>>30 ili kukamilisha nyumba yake ya miti.