Question: Building one birdhouse requires 7 planks and 20 nails. If 1 nail costs $0.05, and one plank costs $3, what is the cost, in dollars, to build 4 birdhouses? Think carefully first, then make a decision:
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. So the answer is 88.