Tag: maths

Questions Related to maths

The sum of the digit of a two-digit number is $\frac { 1 }{ 5 } $ of the difference between the number and the number obtained by interchanging the positions of the digit. What is definitely the difference between the digit of that number ?

  1. 5

  2. 7

  3. 9

  4. Data inadequate

  5. None of these


Correct Option: A

The sum of the digits of a two-digit number is 9 less then the number. Which of the following digits is at unit's place of the number ?

  1. 1

  2. 2

  3. 4

  4. Data inadequate


Correct Option: A
Explanation:
Let $x,y$ are the digits of a number. Then the number $= 10x+y$

as per condition : $10x+y-9 = x+y$

Then as per the given problem,

$x+y=10x+y-9$

or, $9x=9$

or, $x=1$

So, we can say that for any value of y from 1 to 9, the condition satisfies.

for eg: if the number is 18

18–9 = 1+8

9=9 , satisfied.


So the tenth's place digit is $1$.

Get the algebraic expression in the following cases using variables, constant and arithmetic operations.
Subtraction of $z$ from $y$.

  1. $y+z$

  2. $y-z$

  3. $z-y$

  4. $None\ of\ these$


Correct Option: B
Explanation:

Subtraction of $z$ from $y$ implies that a number of value $z$ is to be subtracted from another number of $y$ value $y$ which means $y-z$.

Two years ago the mean age of $40$ people was $11$ years. Now a person left the group and the mean age is changed to $12$ years, then the age of the person who left the group is?

  1. $52$ years

  2. $48$ years

  3. $54$ years

  4. None of these


Correct Option: A

Five years ago Anjali's age was twice Sarita's age. Five years hence, their ages will be $4 : 3$. Anjali's present age is 

  1. $15$ years

  2. $10$ years

  3. $12$ years

  4. $16$ years


Correct Option: A

Kiran is 24 years older than Rakesh. 10 years back Evans age was five times the age of Rakesh. Find the present age of Rakesh.

  1. $40 years $

  2. $16 years$

  3. $20 years$

  4. $36 years


Correct Option: A

A game is played by three players. The loser has to triple the money of each of the other players has. Three games are played and each one losses a game. At the end all have the same amount namely $Rs.\ 54$. The amount the first loser has at the begining is

  1. $Rs.\ 120$

  2. $Rs.\ 112$

  3. $Rs.\ 110$

  4. $Rs.\ 90$


Correct Option: A

When a two digit number is reversed, the new number is reduced by $63$ and the sum of digits of these individual numbers is $9$. Now, if these numbers are converted into base $'x'$ the larger number becomes $5$ times that of smaller one, then the value of $x$ is :

  1. $36$

  2. $13$

  3. $15$

  4. $8$


Correct Option: A

A tree, in each year, grows $5\ cm$ less than it grew in the previous year. If it grew half a meter per year, then the height of the tree (in meters), when it ceases to grow, is

  1. $2.50$

  2. $2.00$

  3. $3.00$

  4. $2.75$


Correct Option: A

The sum of present ages of a father and his son is $10$ years more than the present age o mother. If the mother is $15$ years older than the son, then find the age of father after $5$ years.

  1. $20$ years

  2. $25$ years

  3. $40$ years

  4. $30$ years


Correct Option: A