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Bunuel
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Wendy, Yvonne, and Elizabeth are baking cookies for a bake sale. Wendy 01 Nov 2018, 00:48
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E
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86% (02:12) correct 14% (02:30) wrong based on 90 sessions

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Wendy, Yvonne, and Elizabeth are baking cookies for a bake sale. Wendy can bake all of the cookies in 10 hours, Yvonne can bake half of the cookies in 3 hours, and Elizabeth can bake a third of the cookies in 5 hours. If Wendy and Elizabeth bake for 2 hours, how long will it take Yvonne to finish baking the rest of the cookies?

A. 1.8
B. 2
C. 3
D. 3.6
E. 4
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E
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Wendy, Yvonne, and Elizabeth are baking cookies for a bake sale. Wendy 01 Nov 2018, 01:29
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W does 1/10 work in 1 hour
Y does 1/6 work in 1 hour
E does 1/15 work in 1 hour
In 2 hour W & E does 2*(1/10 + 1/15) = 2/6 work
Y takes (4/6) / (1/6) = 4 hour
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Wendy, Yvonne, and Elizabeth are baking cookies for a bake sale. Wendy 01 Nov 2018, 01:50
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Bunuel
Wendy, Yvonne, and Elizabeth are baking cookies for a bake sale. Wendy can bake all of the cookies in 10 hours, Yvonne can bake half of the cookies in 3 hours, and Elizabeth can bake a third of the cookies in 5 hours. If Wendy and Elizabeth bake for 2 hours, how long will it take Yvonne to finish baking the rest of the cookies?

A. 1.8
B. 2
C. 3
D. 3.6
E. 4
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W, Y and E are baking cookies at different rates. W & E bake cookies for two hours, how long would Y take to bake the rest of the cookies? is the question.

In one hour W bakes 1/10th of cookies.

E can bakes all the cookies in 15 hours.
In one hour E bakes 1/15th of cookies.

Working together for two hours,

In one hour, W + E = 1/10 + 1/ 15 = 5 / 30 = 1/6 of the cookies.

In two, 1/3rd of the cookies are baked.

So Y needs to come in and bake 2/3rd of the cookies.

She takes 3 hours to bake 1/2 the cookies

So she takes 6 hours for all the cookies and 2/3rd of that to bake 2/3rd of the cookies... or 2/3 * 6 = 4 hours.

Hence Option (E) is our choice.

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Wendy, Yvonne, and Elizabeth are baking cookies for a bake sale. Wendy 21 Jun 2022, 08:27
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R=w/t
1/10=W
1/6=y
1/15=E

(W+E =2 hours)

1/10+1/15=1/2
5/30=x/2
1/3 (work done by W and E )

Remaining work

1- 1/3 = 2/3

R=w/t

1/6=2/3÷x

X= 4

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Wendy, Yvonne, and Elizabeth are baking cookies for a bake sale. Wendy 21 Jun 2022, 09:05
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Bunuel
Wendy, Yvonne, and Elizabeth are baking cookies for a bake sale. Wendy can bake all of the cookies in 10 hours, Yvonne can bake half of the cookies in 3 hours, and Elizabeth can bake a third of the cookies in 5 hours. If Wendy and Elizabeth bake for 2 hours, how long will it take Yvonne to finish baking the rest of the cookies?

A. 1.8
B. 2
C. 3
D. 3.6
E. 4
Show more

I hate fractional jobs. Let's just make up a number of cookies. 60 looks like it'll work well.
Wendy can bake 60 cookies in 10 hours, so she bakes 6/hour.
Yvonne can bake 30 cookies in 3 hours, so she bakes 10/hour.
Elizabeth can back 20 cookies in 5 hours, so she bakes 4/hour.
Together, they bake 20/hour, so in 2 hours, they bake 40.
That leaves 20 for Yvonne to bake on her own. At a rate of 10/hour, it'll take 2 hours.

Answer choice B.


There's no variable in the question, but the instinct is to make up a variable out of thin air. Why would we work with X? If we are going to make something up, let's at least make it the easiest thing to work with. We are plugging in for a hidden variable.

ThatDudeKnowsHiddenPlugIn
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