Tina can weed her vegetable garden in 30 minutes.Marisa can do the same task in 40 minutes. If they work together how long will it take them to weed the garden?

Question

Need help solving this algebra word problem.

Answer 1

Every minute, Tina weeds 1/30 of her garden.

Every minute, Marisa weeds 1/40 of her garden.

So:

(1/30 + 1/40)m = 1, where m = number of minutes.

 

We need a common denominator. In this case, it will be 120:

(4/120 + 3/120)m = 1

(7/120)m = 1

m = 120/7

m = 17 1/7

 

So if they work together, it will take 17 ¹/₇ minutes.