if it takes pean 15 minutes to make a swan, and it takes iss 20, how many swans could they make working together in 7 minutes
To solve this problem, we need to find the individual rates of Pean and Iss first.
Pean takes 15 minutes to make 1 swan, so his rate is 1 swan / 15 minutes.
Iss takes 20 minutes to make 1 swan, so his rate is 1 swan / 20 minutes.
To find the combined rate, we add their individual rates:
Combined rate = Pean's rate + Iss's rate
Combined rate = 1/15 + 1/20
Combined rate = (4 + 3) / 60
Combined rate = 7/60
Now, we can calculate how many swans they can make working together in 7 minutes:
Swans made = Combined rate x Time working together
Swans made = (7/60) x 7
Swans made = 49/60
Therefore, they can make 49/60 of a swan working together in 7 minutes.