Some Interview Questions

[kirylm]

1.
The mass of a ripe tomato is composed 99% of water and 1% of other stuff. You put 100 pounds of ripe tomatoes out in the sun. After a while evaporation changes the composition to 98% water and 2% other stuff. At this time, how much do the tomatoes weigh, in pounds?

a) 98
b) 49
c) 50
d) 49.5

2.
A factory recycles and re-manufactures all the paper cups it uses in its cafeteria. It can make one new cup out of 9 used ones. If it currently has 505 used cups, how many re-manufactures cups can be used before externally produced ones are needed?

a) 57
b) 56
c) 65
d) 63

3.
Assume that all cows graze at the same rate. If three cows could graze in a field for a three days until all grass is eaten up, and two cows could graze in the same field for six days, how many days could one cow graze in the field and finish off all the grass? Do not forget that grass keeps growing!

a) 24
b) 21
c) 27.5
d) Forever!

4.
Strictly speaking, which is the simplest correct C program?

A)
main()
{
}

B)
main()
{
return 0;
}

C)
main()
{
exit(0);
}

a) A only
b) B only
c) C only
d) B and C

5.
What would be the preferred macro definition for the absolute value function?

a) #define abs (x) x>0?x:-x
b) #define abs (x) (x)>0?(x)-x)
c) #define abs (x) ((x)>0?(x)-x))
d) #define abs (x) (((x)>0?(x)-x)))

 

[lalala]

ccdb? Do correct me if i'm wrong

 

[kirylm]

ccdb? Do correct me if i'm wrong

Can you explain why 1st question is C?

I am getting d) on the second question:

505 / 9 = 56 re-manufactured and 1 used
we use 56 re-manufactured and end up with 57 used
57/9 = 6 re-manufactured and 3 used left
we use those 6 re-manufactured and end up with 9 used
which makes 1 re-manufactured that we can use as well.
Total re-manufactured used: 63

Can you also explain why is it d) for 3rd one?

I am pretty sure that 4th question's answer is (a).

 

[euroazn]

I believe he is venturing guesses for the first four questions.

 

[kirylm]

I believe he is venturing guesses for the first four questions.

oops...it was a long day ...

 

[pruse]

Can you explain why 1st question is C?

from the given info you know "other stuff" is 1%, i.e. 1 pound. that 1 pound of other stuff stays 1 pound of other stuff because only water evaporates. it becomes 2% of the total, so 98% (=49*2%) is then 49*1=49 pounds, so the total is 1+49=50 pounds.

 

[Azharo]

from the given info you know "other stuff" is 1%, i.e. 1 pound. that 1 pound of other stuff stays 1 pound of other stuff because only water evaporates. it becomes 2% of the total, so 98% (=49*2%) is then 49*1=49 pounds, so the total is 1+49=50 pounds.

Mass and weight are not the same thing. If you are going to assume that in this problem mass and weight are equivalent then the water itself weighs 99 pounds. It is much more likely that the tomatoes now weigh 98lbs because a 1% drop in water mass should not be enough to drop the weight of the tomatoes by half.

 

[PierreXu]

1). C. Assume the weight of "other stuff" doesn't change---remains at 1. Then we need to solve 1/X=0.02=>X=50.
2). D. See kirylm's explanation.
3). D. Assume grass grows with a constant rate v ton/day; each cow grazes at the rate z ton/day. The initial grass volume is y ton. Then
y+3v=9z
y+6v=12z,
therefore v=z.

 

[kirylm]

1). C. Assume the weight of "other stuff" doesn't change---remains at 1. Then we need to solve 1/X=0.02=>X=50.
2). D. See kirylm's explanation.
3). D. Assume grass grows with a constant rate v ton/day; each cow grazes at the rate z ton/day. The initial grass volume is y ton. Then
y+3v=9z
y+6v=12z,
therefore v=z.

agreed on 1 and 3

 

[lalala]

oops sorry it should be 63 for ques 2, I added the used 2 accidentally. i love this kind of ques:D.