word problem: How long would it take Rod to cut grass alone?

Quadratic equations and inequalities, variation equations, function notation, systems of equations, etc.
kyl367
Posts: 6
Joined: Thu Feb 18, 2010 2:12 am
Contact:

word problem: How long would it take Rod to cut grass alone?

Postby kyl367 » Wed May 12, 2010 5:40 pm

Marcie can cut the grass in 3 hrs. working alone. When her younger brother Rod helps, it takes 2 hrs.
How long would it take Rod to cut grass alone?
grass/marcie alone = 3 hrs
grass/marcie and rod = 2 hrs

User avatar
stapel_eliz
Posts: 1738
Joined: Mon Dec 08, 2008 4:22 pm
Contact:

Postby stapel_eliz » Wed May 12, 2010 11:18 pm

kyl367 wrote:Marcie can cut the grass in 3 hrs. working alone. When her younger brother Rod helps, it takes 2 hrs.
How long would it take Rod to cut grass alone?

To learn how to set up and solve this sort of exercise, try here. :wink:

Once you understand the basic terms and techniques, do the standard set-up:

. . .time to complete task:
. . . . .Marcie: 3
. . . . .Rod: r
. . . . .together: 2

. . .portion completed per time unit:
. . . . .Marcie: 1/3
. . . . .Rod:
. . . . .together:

Complete the table, add the input amounts per unit time, set equal to the output amount, and solve for the variable.


Return to “Intermediate Algebra”