If you remove one from eleven, it becomes ten. If you remove one from nine, it becomes ten.
How is this possible ?
It is possible if you are using Roman Numerals.
9 = IX
10 = X
11 = XI
Now it is all possible.
You ask your friend to pick a random number and you have to make five guesses in order to find the number. You write all your guessed numbers on a paper and the differences between the guessed number and the picked number is written on another paper.
After that, one number is erased from each of the paper. Now there are only four numbers on each paper:
Guesses: 27, 32, 44, 45
Differences: 5, 7, 10, 13
Can you find out what is the number?
37
The number is 37.
The missing guess can be either 24 or 50 and the missing difference is 8.
A mathematics teacher took exam of his students. Out of the total students, 25% of the students passed both the tests included in the exam. However, only 42% were able to clear the first test.
Can you find out the percentage of those students who passes the first test and also passed the second test ?
60%
Explanation:
This type of questions call in for the application of conditional probability as the question is asking you to find out the probability that the second test was passed with the given situation that the first one was passed.
The formula for conditional probability:
P (Second/First) = P (First and Second)/ P (First)
= 0.25/0.42
=0.60
=60%
If you keep rolling a pair of dice together till a sum of 5 or 7 is obtained, then what is the probability that a sum of 5 comes before a sum of 7?
This can be solved in a generic and complex way but let us not go into all that.
There can be four ways through which the pair of dice results in a sum of 5. There can be six ways through which the pair of dice can result in a sum of 7.
Now, we want the probability of the pair of dice resulting in a sum of 5 before a sum of 7. Thus probability = 4/(4+6) = 4/10 or 2/5.
Consider the situation that there is a pond where some flowers have grown up and some bees are hovering over the flowers. Now read the following statements carefully:
1. If each of the bees lands on a flower, then one bee does not get a flower.
2. If two bees share each flower, then there is one flower left.
Now, can you calculate the number of flowers in the pong and the number of bees hovering over them?
There are three flowers in the pond and four bees are hovering over it.
How high will you have to count before you use the letter A?
One Thousand
Adam gave half of the apples he had plus one more to Eve. He gave half of the remaining ones plus one more to Diana. Now, Adam was left with just one apple.
Can you find out how many did he have in the beginning?
10
In such type of questions we can come to a conclusion by working our way backwards.
He is left with one apple in the end. He gave half of what he had plus one to Diana. If we remove the extra one, the he must have had two apples. Since now both of them have half of the remaining ones, it must be 2 * 2 = 4 apples.
Again move back. Adam gave half of what he had plus one extra to Eve. Thus if we remove that extra one and give it back to Adam, then Adam must have 5 apples. Since he gave half to Eve, it means he must have had 5 * 2 = 10 apples in the beginning.
Thus Adam had 10 apples in the beginning.
If we roll two dices (six sided normal dice) together.
what is the probability that the first one comes up with a 2 and the second one comes up with a 5?
The probability will be 1/36.
For the first dice, there can be six possibilities. Similarly, for the second dice as well, there can be six possibilities.
Thus the total possibilities is 6 * 6 = 36.
The outcome we need is that the first comes up with a 2 and the second comes up with a 5. That is possible only in one possibility.
Therefore the required probability is 1/36.
Calculate the number of degree between the hour hand and the minute hand of an analogue clock that is displaying a time of 3:15 at present.
This question can be a bit tricky. But if you pay attention, you can solve it. When fifteen minutes have passed after three, the hour hand must have moved exactly one fourth of an hour. Thus both the hands will make an angle of 7.5 degree between them.
Place a mathematical symbol between the numerals 5 and 9 in such a way that the resulting number is greater than 5 but smaller than 9.
If we place a decimal between the numbers it will become 5.9 which is what we needed.