Question

the average of five numbers is 18 the average of first two numbers is 65 and that of the last two numbers is 85 find the third number​

Answer 1

Answer:

-210

Step-by-step explanation:

Given in the question

The average of five numbers = 18

Total = 18*5 = 90

The average of first two numbers = 65

So Total of first two numbers = 65*2 = 130

Average of last two numbers = 85

Total of last two numbers = 85*2 = 170

Lets assume third number is X

Average can be calculated as

Average = sum of all numbers/n

90 = 130 + X + 170

X = 90 - 300 = -210

So Third number is -210