Question

Average of 3 number is 7 average of 1st two number is 5 . Then Which is third number​

Answer 1

Answer:

2

Step-by-step explanation:

let three numbers be A,B,C

given that ,

A+B+C = 7 and A+B =5

now,

5+C=7 ( Because A+B=5)

C=7-5

C=2

Answer 2

Answer:

given 3 numbers 5,5 and 'x'

average of 3 numbers is 7

average = sum/total number

    7        = (5+5+x)/3

    7         = (10+x) / 3

  7×3       = 10+x

 21-10      =   x

          11   =  x