I'm in fourth grade and here's the problem.

Robin's class is developing a community garden. There are 15 students in Robin's class. They volunteer to work in a community garden at various times during the school week. Robin's teacher says it will take about 3 weeks to complete the project if 3 students work 1 hour each day. Some students can work on more than one day. The following table lists the number of students who can work on various days.

1. How many hours would students have to work each week in order to finish the garden on time? I think it would be 15 hours. 3 x 5 = 15 x 3 wks = 45 hours.
    
   
2. Will 3 students be working every day? I put no.
    
   
3. This one I don't understand. On the second week of the project, the whole class is taking a field trip on Friday. How many students will have to work on a different day that week? Explain. My dad thinks 2. I thought 5. Which is it?
    
   
4. The students worked for 12 hours a week during the first two weeks.
   • How many hours will they need to work in the third week in order to complete the garden on time? I put 21 hours. 45 hours - 24 hours = 21
      
     
   • How many hours should each student work in the final week in order to complete the garden on time? Explain. I put 15 into 21 and got 1 r. 6. Does that mean 1.6 hours or how else do you write it if that is correct.

I just need to know the answers to #3 and #4. I didn't quite understand them.
Thanks for your help. Adam

Hi Adam,

I'm not sure about 3 either. I think that the answer is probably 5 but your father could be right also. After reading part 4 and seeing that you can "catch up" in week 3 then I would say that even 0 is a valid answer to 3.

For part 4 I agree with your answer. As to how to write 1 r. 6 hours, I suggest that you express it in minutes rather than hours. 21 hours is 21*60 = 1260 minutes. 1260 divided by 15 is 84 minutes which is 60 minutes plus 24 minutes, that is 1 hour and 24 minutes.

Cheers,
Penny Go to Math Central