Alice and Jan are decorating the gym with balloons. ALice can inflate 7 balloons every 6 mins. Jan can inflate 4 balloons every 3 mins. Working together, how long will it take them to have 25 balloons ready

Answer 1

alice's rate = (7/6) balloons/min
Jan's rate = 4/3 balloons/min
combined rate = (7/6 + 4/3) balloons/min = 5/2 balloons/min

time to do 25 balloons = 25/(5/2) minutes = 10 minutes

Answer 2

7 balloons = 6 minutes 11 balloons = 9 minutes 4 balloons = 3 minutes
so

22 balloons = 18 minutes
it will take about 24 1/2 minutes for 25 balloons.