Solution:

Two men and seven women complete the work in four days
Or we can say that eight men and twenty eight women complete the work in one day

Also,
Four men and four women complete the work in three days
Or we can say that twelve men and twelve women complete the work in one day

Now we know that the work is same

8 men + 28 women = 12 men + 12 women
1 man = 4 women

Put it into any equation
Four men and four women complete the work in three days
Or four men and one man complete the work in three days
= Five men complete the work in three days
= One man complete the work in three*five = fifteen days

Solution:

The most often answer is 0 which is completely wrong.

Let us begin like this. The 12 hours in a clock makes a total of 360 degrees. Thus one hour will equal to 30 degrees.

Now as per the question, the hour hand will directly be on 3 when the minute hand is at 12. After 15 minutes or after 1/4 of an hour i.e. at 3:15, the hour hand will be 1/4 * 30 degrees = 7.5 degrees away from the minute hand.

Solution:

This is a bit tricky question that almost every time leaves the interviewee baffled.

Now take into consideration that the first friend can have his birthday in any of the months (there are 12 months all together).

All you have to find out is the probability that the second one will have his birthday in the same month which is a piece of cake.

The probability = 1/12.

Solution:

According to the question
19W + 21B = 562 (where W stands for white bricks and B stands for black bricks)

The easiest way to solve this problem would be putting in the values for W, till we achieve an answer which is divisible by 21.
Why? Because it is must for the statement to be true.

If W = 1
21B = 562 - 19 = 543 i.e. not divisible

If W = 2
21B = 562 - 38 = 524 i.e. not divisible

If W = 3
21B = 562 - 57 = 505 i.e. not divisible

If W = 4
21B = 562 - 76 = 486 i.e. not divisible

If W = 5
21B = 562 - 95 = 467 i.e. not divisible

If W = 6
21B = 562 - 114 = 448 i.e. not divisible

If W = 7
21B = 562 - 133 = 429 i.e. not divisible

If W = 8
21B = 562 - 152 = 410 i.e. not divisible

If W = 9
21B = 562 - 171 = 391 i.e. not divisible

If W = 10
21B = 562 - 190 = 372 i.e. not divisible

If W = 11
21B = 562 - 209 = 353 i.e. not divisible

If W = 12
21B = 562 - 228 = 334 i.e. not divisible

If W = 13
21B = 562 - 247 = 315 i.e. divisible

Thus W must be 13 and if W = 13
B = 315/21 = 15

Thus to form that tower, 13 white bricks and 15 black bricks will be required.

Solution:

You may solve this question with different methods but we are only giving away one.

What you have to do in that method is look for a number x to which all the numbers from 2 to 10 divide evenly. Multiplying the numbers together (2*3*4*5*6*7*8*9*10) will give you a big number but we have to find a smaller possibility. What we can do is find the prime factors, a subset of which we can use to form a number from 2 to 10.

2*2*2*3*3*5*7 will certainly give us what we need. The product is 2520 and it is the lowest possible number which can be evenly divided by 2-10.

Now if we add 1 to the number, the result will be 2521 which will satisfy all the conditions from 2 to 10. But will not hold true in case of 11.

If you calculate, you will see that you can multiply 2520 by any integer and add 1 to it to satisfy all the conditions except the divisibility by 11. What we need is an integer Y that can be multiplied by 2520 and if we add 1 to the product, it becomes divisible by 11.

2520/11 leaves a remainder 1. Now let us keep increasing the number of 2520. Suppose if we divide two 2520 by 11, the remainder then will be 1 + 1 = 2. If we keep going on like that. Ten 2520 when divided by 11 will give 10 as remainder and if we add 1 to them, it will be completely divisible. Also it will satisfy all the conditions from 2-10.

Thus our answer is 25201.

Solution:

90

Split the cube into three by three grids. You will get three layers. Now get to one square from the cell adjacent instead of counting the path. You can now count the paths from the left (x), the right (y) and the level above (z). So the path for any square will be x + y + z.

Solution:

If you have come up with the fact that the bugs can avoid the collision only when they decide to move in the same direction be it clockwise or anti clockwise, you have already solved half of it. In any other way, the bugs will definitely run into each other.

Now the bugs can move either clockwise or anti-clockwise. The probability of choosing a specific direction is then 1/2.

We will utilize the simple equation of probability to find out our answer

P(No Collision) = P (The bugs move in clockwise direction) + P(The bugs move in anti-clockwise direction)
= 0.5 * 0.5 * 0.5 + 0.5 * 0.5 * 0.5
= 0.25

Thus the probability that the bugs won't collide into each other is 0.25 or 1/4.

Solution:

To solve this question, we will have to use the concept of relative speed.

Let us assume that the distance between the station A and B is D Miles
The relative speed at which the train are approaching each other is 20 + 15 = 35 mph
When the train collides with each other, the sum of the distance covered will be the distance between the stations i.e. D.
Now Speed = Distance/Time
Which means that the trains will collide in d/35 hours after their start

Another constant things we have here is the speed of the vulture i.e. 25 mph.
Thus by the time the trains collide, the vulture would have covered
25*(D/35) miles = 5D/7 Miles

Solution:

In this question, let us think through the mind of Lincoln. At the first information of the product of the ages being 72, he must have calculated the number of ways in which the three ages can be multiplied in order to obtain 72. Of course there are many ways and therefore he asked for more info. Then Michael tells him how to find the sum of the ages of his children. Of course, we don't know what he saw. But he said that the information was still not enough.

Now why did he say so? It is because there must be two permutations with the same sum or he would have identified the ages easily. Now what are those two permutations?

The two possible permutations are 8 3 3 and 6 6 2. Both of them adds up to 14 (which would be the bar's address).

The last hint by Michael was that his youngest child loves to eat strawberry ice cream. The term youngest means that there is only one youngest child. If you see the permutation 8 3 3, it will mean that there are two youngest children. Thus it does not stand valid with the third hint. So, we are only left with one possibility i.e. 6 6 2.

Thus the ages of his children are 6, 6 and 2.

Solution:

Total percentage in eight examinations = 55
Total marks obtained = 55% of Maximum marks (8x100) = 55*800/100 = 440
Now, she scored 15% of these marks in Mathematics

Thus the score in mathematics = 440*(15/100) = 66

Hence, Anabelle scored 66 marks in Mathematics.