SOLUTION: Karla cleaned her garden by raking.she took 40 min to finish. mike took 60 min for the same place to clean.if karla started 10 minutes before,How much time will take to fish clean

Question 615963: Karla cleaned her garden by raking.she took 40 min to finish.
mike took 60 min for the same place to clean.if karla started 10 minutes before,How much time will take to fish cleaning together?

Found 2 solutions by josmiceli, Edwin McCravy:
Answer by josmiceli(19441) (Show Source): You can put this solution on YOUR website!
Add their rates of cleaning to get their rate working together
Karla's rate: ( 1 garden cleaned ) / ( 40 min )
Mike's rate: ( 1 garden cleaned ) / ( 60 min )
---------
What fraction of the job did Karla get done in 10 min?

So, 1/4 of the garden is cleaned before they both start working together
That means 3/4 of the garden is left to clean
Let = the time in minutes for them to finish working together

Multiply both sides by

it takes them 18 minutes to finish together
check:

OK
Answer by Edwin McCravy(20059) (Show Source): You can put this solution on YOUR website!
Karla cleaned her garden by raking.she took 40 min to finish.
mike took 60 min for the same place to clean.if karla started 10 minutes before,How much time will take to finish cleaning together?

Let x = the answer. Make this chart and put x for the time Karla and Mike rake together. Number of Time Raking gardens raked raked Rate or fraction in in thereof minutes gardens/min Karla alone raking 1 garden Mike alone raking 1 garden Karla raking alone 10 minutes Karla and Mike raking together x ------------------------------------------------------------------------- Karla takes 40 minutes to rake 1 garden so put 40 for her time and 1 for the number of gardens she rakes in 40 minutes. Number of Time Raking gardens raked raked Rate or fraction in in thereof minutes gardens/min Karla alone raking 1 garden 1 40 Mike alone raking 1 garden Karla raking alone 10 minutes Karla and Mike raking together x ------------------------------------------------------------------------- Mike takes 60 minutes to rake 1 garden so put 60 for his time and 1 for the number of gardens he rakes in 60 minutes Number of Time Raking gardens raked raked Rate or fraction in in thereof minutes gardens/min Karla alone raking 1 garden 1 40 Mike alone raking 1 garden 1 60 Karla raking alone 10 minutes Karla and Mike raking together x ------------------------------------------------------------------------- Fill in their rates in gardens/minute by dividing the number of gardens by the number of minutes: Number of Time Raking gardens raked raked Rate or fraction in in thereof minutes gardens/min Karla alone raking 1 garden 1 40 1/40 Mike alone raking 1 garden 1 60 1/60 Karla raking alone 10 minutes Karla and Mike raking together x ------------------------------------------------------------------------- Karla's rate for the 10 minutes she worked alone is the same as when she rakes 1 whole garden so fill in 1/40 for her rate there too, and 10 for the number of minutes: Number of Time Raking gardens raked raked Rate or fraction in in thereof minutes gardens/min Karla alone raking 1 garden 1 40 1/40 Mike alone raking 1 garden 1 60 1/60 Karla raking alone 10 minutes 10 1/40 Karla and Mike raking together x ------------------------------------------------------------------------- Find the fraction of a garden Karla raked in those 10 minutes by multiplying her rate in gardens/min by the number of min: 10(1/40) = 1/4. Fill that in: Number of Time Raking gardens raked raked Rate or fraction in in thereof minutes gardens/min Karla alone raking 1 garden 1 40 1/40 Mike alone raking 1 garden 1 60 1/60 Karla raking alone 10 minutes 1/4 10 1/40 Karla and Mike raking together x ------------------------------------------------------------------------- Find their combined raking rate by adding their rates: 1/40 + 1/60 = 3/120 + 2/120 = 5/120 = 5/120 = 1/24. Fill that in: Number of Time Raking gardens raked raked Rate or fraction in in thereof minutes gardens/min Karla alone raking 1 garden 1 40 1/40 Mike alone raking 1 garden 1 60 1/60 Karla raking alone 10 minutes 1/4 10 1/40 Karla and Mike raking together x 1/24 ---------------------------------------------------------------------- Find the fraction of a garden they raked together by multiplying their combined rate 1/24 by the number of minutes x, getting x/24. Fill that in: Number of Time Raking gardens raked raked Rate or fraction in in thereof minutes gardens/min Karla alone raking 1 garden 1 40 1/40 Mike alone raking 1 garden 1 60 1/60 Karla raking alone 10 minutes 1/4 10 1/40 Karla and Mike raking together x/24 x 1/24 The equation comes from: + = + = 1 Multiply both sides by 24 6 + x = 24 x = 18 It took the 18 minutes to finish. Edwin

RELATED QUESTIONS
It took Karla and her helper 24 minutes to feed 18 cats. Working at the same rate, how... (answered by scott8148)
The problem is - It took Karla & her helper 24 minutes to feed 18 cats. Working at the... (answered by ankor@dixie-net.com,MRperkins)
It takes beverly 4 hours to clean a room. If steve worked together with her it would only (answered by ptaylor)
Callie took 20 min to drive her boat upstream to water ski at her favorite spot. Coming... (answered by ewatrrr)
Angela takes 40 minutes to dust and clean her home while her sister rani takes an hour... (answered by nerdybill)
Wanda has read 80 of the 118 pages in a book. It took her 2 hours, 40 min. It is now... (answered by nycsharkman,ankor@dixie-net.com)
Sally had a doctor's appt. at 10am and decided she would take the bus. It took her 10... (answered by ankor@dixie-net.com)
Ingrid can rake our lawn in 90 min ad I can do it in 60 min. If she rakes for 15 min... (answered by ankor@dixie-net.com)
Jane took 30 min to drive her boat upstream to water-ski at her favorite spot. Coming... (answered by stanbon)