Question

The average of three numbers is 70. The first number is twice the second and the second number is twice the third. Find the first number.

Answer 1

The first no is 30, 2nd no is 60 and 3rd no is 120.

Answer 2

Answer: First number is 120.

Step-by-step explanation:

Let the three numbers be a,b and c respectively.

Average of three numbers can be found by:

Average= (a+b+c)/3

Here, as given in the question:

Average= 70

The relation between the three numbers are given as-

a= 2b or b = a/2 ; b = 2c

Therefore, b= a/2 = 2c so a= 4c

Representing all the numbers in terms of c:

a/2= 2c ; a= 4c

b= 2c

Average= ( 4c + 2c + c)/3 = 7c/3

Therefore, 7c/3 = 70 , so c= 30

So, b = 60 and a= 120

Answer: The first number is 120.