Jeremy worked for 8 1/2 hours building model airplanes,
If each airplane takes him 1 2/5 hours to make, how many models did he build?
To find the number of models Jeremy built, we need to divide the total time he worked, which is 8 1/2 hours, by the time it takes him to make one model, which is 1 2/5 hours.
First, we need to convert 8 1/2 hours to a mixed number. To do this, we need to find a common denominator for 2 and 5, which is 10.
8 1/2 = 8 + 1/2 = 8 + 5/10 = 8 + 1/10 + 4/10 = 8 1/10
Therefore, Jeremy worked for a total of 8 1/10 hours building model airplanes.
Next, we need to convert 1 2/5 hours to a mixed number:
1 2/5 = 1 + 2/5 = 1 + 4/10 + 2/10 = 1 4/10
Therefore, it takes Jeremy a total of 1 4/10 hours to make one model airplane.
Now, we can divide the total time Jeremy worked by the time it takes him to make one model:
(8 1/10) ÷ (1 4/10) = (81/10) ÷ (14/10) = (81/10) × (10/14) = (81 × 10) ÷ (10 × 14) = 810/140 = 81/14 ≈ 5.7857
Therefore, Jeremy built approximately 5.7857 models.
However, since it is not possible to build a fraction of a model, we can conclude that Jeremy built a total of 5 models.