Evan's favorite hobby is origami. He plans to make 100 paper cranes to hang from the ceiling of his bedroom. Yesterday, he made 28 paper cranes in 4 hours. Today, he made 21 paper cranes at the same rate.

Question

How long did Evan spend making paper cranes today?

Answer 1

To determine how long Evan spent making paper cranes today, we first need to find his rate of making cranes.

Yesterday, Evan made 28 paper cranes in 4 hours. We can calculate his rate as follows:

\[ \text{Rate} = \frac{\text{Number of cranes}}{\text{Time in hours}} = \frac{28 \text{ cranes}}{4 \text{ hours}} = 7 \text{ cranes per hour} \]

Today, Evan made 21 paper cranes. To find out how long he spent making these cranes, we can use the rate we calculated.

Let \( t \) be the time in hours he spent today. We know:

\[ \text{Cranes made} = \text{Rate} \times \text{Time} \Rightarrow 21 \text{ cranes} = 7 \text{ cranes/hour} \times t \text{ hours} \]

Now, we can solve for \( t \):

\[ t = \frac{21 \text{ cranes}}{7 \text{ cranes/hour}} = 3 \text{ hours} \]

Thus, Evan spent 3 hours making paper cranes today.