 
 <prompt> N'ime ihe mere birdhouse onye na-eme 7 planks na 20 nails. Ọ bụghị ịkpa 1 na-eme $0.05, ma ịkpa 1 na-eme $3, gịnị ka ịkwụsị, n'ọnụ, iji kwụsị 4 birdhouses? <response>: The cost of the planks for one birdhouse is 7 * 3 = $21.
And the nails are a cost of 20 * 0.05 = $1 for each birdhouse.
So to build one birdhouse one will need 21 + 1 = $22.
So the cost of building 4 birdhouses is at 4 * 22 = $88.

The answer will be 88. 