Sophie and Simon are peeling a pile of potatoes for lunch in the cafeteria. Sophie can peel all the potatoes by herself in 45 minutes, while it would take Simon 30 minutes to do the job working alone. If Sophie and Simon work together to peel the potatoes, how long will it take them?
+130536 Sophie does 1/45 of the job in one minute and Simon does 1/30 of the job in one minute.....let x be the time it takes to do the job [in minutes] working together....and we have......
(1/45)x + (1/30)x = 1 ..... where "1" represents the completed job......getting a common denominator, we have
[30 + 45]x / 1350 = 1 simplify
(75/ 1350)x = 1 multiply both sides by 1350/75 and we have
x = 1350/75 = 18 minutes
Call the job of potato peeling 'x' 't' is the new time to do 'x'
Then Sophie's speed is x/45 and Simons speed is x/30
(x/45)t + (x/30)t = x
t(2x/90 + 3x/90) = x
t5x/90 =x
t5/90=1
t=90/5
t=18 minutes
+130536 Sophie does 1/45 of the job in one minute and Simon does 1/30 of the job in one minute.....let x be the time it takes to do the job [in minutes] working together....and we have......
(1/45)x + (1/30)x = 1 ..... where "1" represents the completed job......getting a common denominator, we have
[30 + 45]x / 1350 = 1 simplify
(75/ 1350)x = 1 multiply both sides by 1350/75 and we have
x = 1350/75 = 18 minutes
