Answer:
1. 21 hours
2. 21 hours
Explanation:
1. If we add up all the time it takes them to build one dog house, we get 210 minutes or 3.5 hours. All we have to do is multiply this by 6 because they are building 6 of these exact dog houses. We would then get the answer 21 hours.
2. For this one, it would take Reece double the time it would take both friends. We know if they are both working it takes 3.5 hours so if it is just one of them working it would take 7 hours. So if she builds 3 it will take 21 hours.