What is the average of first 20 multiples of 7 ?

What is the average of first 20 multiples of 7 ?

Answer/Solution

D)84

Steps/Work

Required average = 7(1+2+....+20) / 20
(8/20)X ( (20x21) / 2 ) (because sum of first 21 natural numbers)
= 84
D

General Calculator / Auto Solver

What is the average of first multiples of ?

Calculated Answer

73.5

Step by Step Solution

In order to solve problem, you must evaluate n₁ * ((n₀ * (n₀ + 1)) / 2) / n₀.

n₀ =	20
n₁ =	7

n₁ * ((n₀ * (n₀ + 1)) / 2) / n₀
Evaluate n₀ + 1 = 21
n₁ * ((n₀ * 21) / 2) / n₀
Evaluate n₀ * 21 = 420
n₁ * (420 / 2) / n₀
Evaluate 420 / 2 = 210
n₁ * 210 / n₀
Evaluate 210 / n₀ = 10.5
n₁ * 10.5
Evaluate n₁ * 10.5 = 73.5
73.5
The answer to the problem and the result of n₁ * ((n₀ * (n₀ + 1)) / 2) / n₀ is 73.5