She can see a precut dress in 3 hours. Helen can see the same dress in 2 hours. If they work together, how long will it take to sew the dress?

1 answer

To find the combined rate at which they work together, we add their individual rates.

Helen's rate: 1 dress per 2 hours
Nancy's rate: 1 dress per 3 hours

Combined rate: 1/2 + 1/3 = 5/6 dresses per hour

Therefore, working together they can sew the dress in 6/5 hours or 1.2 hours.

So, it will take them 1.2 hours to sew the dress together.