Question

A group of four numbers has an average (arithmetic mean) of 15

Answer 1

Answer:

x/4+ x/4 + x /4+ x/4 =15

4x/4 = 15

x = 15

so you can say

(15,15,15,15)

OR

x/4 + y/4 + a/4 + b/4 = 15

x+y+a+b = 15*4

x + y + a + b = 60

(14,15,15,16)

(20,20,10,10)

( 5, 25,20,10)

Answer 2

The sum of five numbers = 75

Step-by-step explanation:

The complete question:

A group of four numbers has an average (arithmetic mean) of 15. What is the sum of the five numbers ?

Given,

The average of four numbers = 15

To find, the sum of five numbers = ?

Let the four numbers = a, b, c and d

$\dfrac{a+b+c+d}{4}= 15$

⇒ a + b + c  + d = 60        ..........(1)

The sum of five numbers = The sum of four numbers + 15

= (a + b + c + d) + 15

Using (1), we get

= 60 + 15 = 75

Hence, the sum of five numbers = 75