SOLUTION: Heather and marika recently worked at the community service day at Harvey Scott Elementary School. If it took them 3 hours working together to put bark dust down on the side of the

Question 222878: Heather and marika recently worked at the community service day at Harvey Scott Elementary School. If it took them 3 hours working together to put bark dust down on the side of the school, and it would have taken Heather 5 hours to do it herslef, how long would it take Marika to complete the job by herself?
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
Heather and marika recently worked at the community service day at Harvey Scott Elementary School. If it took them 3 hours working together to put bark dust down on the side of the school, and it would have taken Heather 5 hours to do it herslef, how long would it take Marika to complete the job by herself?
----------------------------------------------
Together DATA:
time = 3 hr/job ; rate = 1/3 job/hr.
--------------------------------------
Heather DATA:
time = 5 hr/job ; rate = 1/5 job/hr
--------------------------------------
Marika DATA:
time = x hr/job ;rate = 1/x job/hr
----------------------------------------
Equation:
rate + rate = together rate
1/5 + 1/x = 1/3
Multiply thru by 15x to get:
3x + 15 = 5x
2x = 15
x = 7 1/2 hrs (time for Marika to do the job alone)
===================
Cheers,
Stan H.
RELATED QUESTIONS
In a statistics class of 54 students, 22 have volunteered for community service in the... (answered by rothauserc)

carlos worked 31.5 hours at a hospital as a volunteer. this represents 87.5% of his... (answered by fractalier,josmiceli)

In a statistics class 45 of students,14 have volunteered for community service in the... (answered by stanbon)

Heather is collecting dimes she saves one dime on the first day two dimes on the second... (answered by jim_thompson5910)

Will you please help me with this problem about creating integer coefficients? The whole (answered by Theo)

Starting from the same point at the same time Samuel and Heather rode their mini-bikes in (answered by ankor@dixie-net.com)

Working alone, it takes Heather 13 hours to tar a roof. Lea can tar the same roof in 15... (answered by Edwin McCravy)

The ratio of boys to girls at an elementary school is 3 to 4. If there are 580 students,... (answered by ankor@dixie-net.com)

Cindy ran from her house to school at an average speed of 6 miles per hour and returned... (answered by josgarithmetic)