working together to pick oranges problem...help with set up?

[soccermom2004]

Ray can pick all of the oranges in 1 row of a grove in 6 hours. Asa can pick all of the oranges in 1 row in 4 hours. If they work together, how long will it take them to pick 15 rows of the grove?

Ok...my first instinct was to add 6 and 4 to get 10 hours to pick 2 rows and set it up as a proportion. However, this gives me 75 hours and the answer is 36 hours. I really need to know HOW to come up with 36 hours. I would appreciate any help with the proper set up.

Thanks!!!!!!

 

[Deleted member 4993]

Re: working together to pick oranges problem...help with set

Ray can pick all of the oranges in 1 row of a grove in 6 hours. Asa can pick all of the oranges in 1 row in 4 hours. If they work together, how long will it take them to pick 15 rows of the grove?

Ok...my first instinct was to add 6 and 4 to get 10 hours to pick 2 rows and set it up as a proportion. However, this gives me 75 hours and the answer is 36 hours. I really need to know HOW to come up with 36 hours. I would appreciate any help with the proper set up.

Thanks!!!!!!

Hint:

Working together, they can pick (1/6 + 1/4 =) 5/12 rows in 1 hour.

 

[soccermom2004]

Re: working together to pick oranges problem...help with set

Thank you!!!

Now I understand the math, but WHY do you add the two fractions together?

 

[Deleted member 4993]

Re: working together to pick oranges problem...help with set

Thank you!!!

Now I understand the math, but WHY do you add the two fractions together?

Good question - I encourage you to think about it a little?

What fraction of one row would Ray pick in ONE hour?

What fraction of one row would Asa pick in ONE hour?

 

[soccermom2004]

Re: working together to pick oranges problem...help with set

Thank you! I've got it now...thanks so much for your help!