# Weighted Averages

Concepts
Examples

When we have to calculate the average of some groups of different things, having different number of elements is being calculated, then it is called the weighted average.

If the number of elements in n different groups be
N_{1},N_{2},N_{3} .. N_{n} and their respective averages be
A_{1},A_{2},A_{3}...A_{n} ,** then Weighted average =**

**Question 1**Average cost of buying 5 quality A crackers is 60 and cost of buying 10 quality B crackers is 80. WHhat will be average cost of buying all the crackers.

71.33 | 72.33 |

73.33 | 74.33 |

**Question 2**Average weight of a class of 40 students is 30 and average weight of a class of 20 students is 15. Find the average weight of both the classes combined.

21 | 22 |

24 | 25 |

**Question 3**There are two sections A and B of a class, consisting of 36 and 44 students' respectively. If the average weight of section A is 40kg and that of section B is 35kg, find the average weight of the whole class.

37.25 | 74.5 |

36.25 | 36 |

**Question 4**Average salary of 12 employees in company A is 15000 pm and 15 employees is company B is 16000 pm. What will be the average salary of all the employees.

17000 | 16888 |

15000 | 14888 |