Question 612342: annie takes 6 hrs to do a project. Mya takes 9hrs. how long will it take them to do a project together? Answer by alicealc(293) (Show Source):
If Annie and Mya work together, the speed will be:
1/6 + 1/9 = 3/18 + 2/18 = 5/18 project/hrs
For 1 project, the time taken if they work together will be: hrs
= 18/5 hrs
= 3 3/5 hrs
= 3 hrs + 3/5 * 60 mins
= 3 hrs + 36 mins
so, if they work together it will take 3 hours and 36 minutes to finish a project