Question

Wendy can wash a car twice as fast as Jason. When they work together, Wendy and Jason can wash a large van in 2 hours. How many hours would it take Wendy to wash the van by herself?

5

3

4

2

Answer 1

Wendy? O.O
:3

Answer 2

y u use tht face?

Answer 3

y not? :>

Answer 4

lol true but can you help me?

Answer 5

I wonder if I can... nobody knows Wendy more than I do ^.^

But... I'm sure it can't possibly take her 2 hours to do it alone, knowing that it takes two hours to do it even with Jason helping out...

Answer 6

Regardless, let's let the time it takes Wendy to do it be w, so, in one hour, how much of the work does she finish?

Answer 7

1

Answer 8

Really? She finishes the entire van in just one hour?
1 means it's finished... I was expecting something less than 1...

Besides, if she can finish the entire van in just an hour, why would it take her two hours with Jason helping out? XD

Answer 9

idk it confuses me when i try to figure it out backwards like this

Answer 10

That's such a pity :D
How do you deal with confusion?

Answer 11

i dont deal wit it.i just guess on it

Answer 12

Oh? What's your guess... let's see if luck's on your side :>

Answer 13

my guess is 3

Answer 14

haha
okay then...

Answer 15

Was it correct, though?

Answer 16

am i right?

Answer 17

I don't know, why don't we find out? :)

Answer 18

idk if it right tht y i asked u if im right

Answer 19

We're about to find out.
In an hour, Wendy gets \(\Large \frac1w\) of the work done, so that in w hours, she gets \(\Large w\times \frac1w \) of the work done, which is equal to 1.

Now Jason, who works half as fast as Wendy, how much work does HE get done in an hour?

Answer 20

\[j=2\times \frac{ 1 }{ w }\]?

Answer 21

That means he gets twice the work done in an hour... which means Jason is actually twice as fast as Wendy... that can't be right, right?
Wrong factor, it's not 2, but... ?

Answer 22

.5?

Answer 23

Right... or 1/2
So in an hour, Jason 'only' gets \(\Large \frac1{2w}\) of the work done...

Answer 24

ok

Answer 25

Now, when they work together, they take two hours to finish, right?

Answer 26

right

Answer 27

right

Answer 28

which means, in an hour, they get HALF the work done.
Putting that in equation, we get
\[\Large \frac1w + \frac1{2w} = \frac12\]
Go ahead and solve for w. :)

Answer 29

so the answer would be 4?

Answer 30

I don't know, is it?
I already gave you the equation to solve, why don't you check it yourself? ^.^

Answer 31

ok thnx

Answer 32

What's your answer?