# Aptitude - Problems on Numbers

- Problems on Numbers - Formulas
- Problems on Numbers - General Questions
- Problems on Numbers - Data Sufficiency 1
- Problems on Numbers - Data Sufficiency 2

Let the number be *x*.

Then, | 1 | of | 1 | of x = 15 x = 15 x 3 x 4 = 180. |

3 | 4 |

So, required number = | 3 | x 180 | = 54. | ||

10 |

Video Explanation: https://youtu.be/z49OUnzTnwY

Let the three integers be *x*, *x* + 2 and *x* + 4.

Then, 3*x* = 2(*x* + 4) + 3 *x* = 11.

Third integer = *x* + 4 = 15.

Video Explanation: https://youtu.be/_77C9YE321Y

Let the ten's digit be *x* and unit's digit be *y*.

Then, (10*x* + *y*) - (10*y* + *x*) = 36

9(*x* - *y*) = 36

*x* - *y* = 4.

Video Explanation: https://youtu.be/7QOJjAmGVx0

Since the number is greater than the number obtained on reversing the digits, so the ten's digit is greater than the unit's digit.

Let ten's and unit's digits be 2*x* and *x* respectively.

Then, (10 x 2*x* + *x*) - (10*x* + 2*x*) = 36

9*x* = 36

*x* = 4.

Required difference = (2*x* + *x*) - (2*x* - *x*) = 2*x* = 8.

Let the ten's and unit digit be x and |
8 | respectively. |

x |

Then, | 10x + |
8 | + 18 = 10 x | 8 | + x |
||

x |
x |

10*x*^{2} + 8 + 18*x* = 80 + *x*^{2}

9*x*^{2} + 18*x* - 72 = 0

*x*^{2} + 2*x* - 8 = 0

(*x* + 4)(*x* - 2) = 0

*x* = 2.