Agree with you - wher is this from

(2) Doesn't tell you their digging rate. A man digging 599kg/hr would finish faster than a man digging 1kg/hr.

I thought it was D initially, but I think it's A now.

Looking at Statement 2:
From the stem, we know how long they worked together (1 hr) and statement 2 gives us the ratio of the time they spent working individually (1/3:2/3) but as pseudononymous pointed out, we can't determine the indvidual rates. There could be multiple values that satisfy the equation.

For example, let x=the man's rate and y=the boys rate. We know how long they worked individually (man=1/3hr. boy=2/3hr). So, the equation would be:

(1/3)x+(2/3)y= 600

(x,y) could = (300,750), (1200, 300), (600,600), ect...

Thus, it's insuffient and the answer is A.

Can we get an expert to weigh in on this one?

To be honest, I don't even understand statement (2).

The original info says:

A man and a boy together dig 600kg of earth in an hour working independently but simultaneously.

And then (2) says:

2)The boy works twice as long as the man

How can they work independently but simultaneously for an hour and the boy work twice as long as the man?

Either statement (2) has been misquoted or this is just a really bad question. What's the source?

Stuart Kovinsky wrote:To be honest, I don't even understand statement (2).

How can they work independently but simultaneously for an hour and the boy work twice as long as the man?

Easy, they work independently but at the same time with each other.
Think synchronized swimming?

The answer is A as stated.

1/timeMan + 1/timeBoy = 1/1
1/1 becase 1/timeTotal

workBoy = 200kg + workMan
workMan + workBoy = 600kg
Can find work done by both people here.

And then just divide workMan/1 hour.

Easy enough and not Ambiguous.

canuckclint wrote:

Stuart Kovinsky wrote:To be honest, I don't even understand statement (2).

How can they work independently but simultaneously for an hour and the boy work twice as long as the man?

Easy, they work independently but at the same time with each other.
Think synchronized swimming?

If they work at the same time as each other, how does the boy work twice as long as the man?

In most GMAT work problems, we see the phrase "independently but simultaneously", or something very similar - I have no problem with that part. I just don't see how they can work simultaneously for different amounts of time - that's a contradiction.