Question

The average of 20 numbers is 15 and the average of first five is 12.what is the average of the rest is?

Answer 1

Step-by-step explanation:

let

total sum of all 20 number is be x.

there for,

x÷20=15

x=20×15

x=300

there for,

by the first condition

first five number average

x-15÷5=12

x-15 =60

x =60+15

x=75

sun of first five number =75

by the second condition

rest 15 number average is

sum of rest 15 number=sum of all numbers- sum of first five number

= 300-75

= 225

there for

average of rest number is followed;

225÷15=15

there for,

average of rest 15 numbers is 15.

Answer 2

Step-by-step explanation:

5× -3 + 15x=0

x =1

average of 15 nos = 15+1 =16