3 tricky questions from GmatPrep!

The first question can be solved without any computations.

The question gives us conditions with regard to Time and Distance.

As one should already know, Rate x Time = Distance

Hence if any of the choices give an indication of the Rate we are sorted, since it will provide us with either a Yes or a No answer (which we don't need to work out in order to answer the question).

1) "less than 6.4 km/h" is an indication of Rate (which can of course be converted into mph)

2) "more than 9 minutes per km" is also an indication of Rate (which can be converted into km/h and than into mph)

So D is the answer.


For the third question, reason it this way:

h(100) = (2^50)*(1*2*3*...50)


h(100) is divisible by 2. So h(100)+1 is not divisible by 2, i.e. 2 is not a factor of h(100)+1.

h(100) is divisible by 3. So h(100)+1 is not divisible by 3, i.e. 3 is not a factor of h(100)+1.

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.
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h(100) is divisible by 50. So h(100)+1 is not divisible by 50, i.e. 50 is not a factor of h(100)+1.


Hence every prime number upto 50 is not a factor of h(100)+1.

So p > 50.

Answer: E

I disagree with you on number 1. We got the same answer but your logic is flawed IMO..
you say a calculation is not necessary.

We have an inequality not simply and equation with an "=" sign..

what if 1) said less than 9 km/hr?

the trip then could have taken less or more than 2 hours.

or what if from 1) and 2) we got some range of time?
1< time <3

Yes, I'm wrong. Apologies. :wink: