Question

Out of 3 numbers the first is twice the second and is half of the third. if the average of three numbers is 56, the difference of first and third number is

Answer 1

Let the 2nd number be x.
Since the 1st number is twice the 2nd, it is 2x.
Since the 1st number is half of the 3rd, i.e., the 3rd number is twice the 1st, the 3rd number is 4x.
The average of the three numbers is 56, so
$\frac{2x + x + 4x}{3} = 56 \\ 7x = 56 \times 3 \\ x = \frac{56 \times 3}{7} \\ x = 8 \times 3 \\ x = 24$
Now the difference between the 1st and the 3rd numbers is
$4x - 2x \\ = 2x \\ = 2 \times 24 \\ = 48$

Answer 2

Answer:

Let the Second number be x.

As the First number is twice the second number. So, the first number will be 2x.

And the First number is half of the Third number. So, the Third number will be 4x.

Step-by-step explanation:

Average of the three numbers= 56

So,

$2x + x + 4x + \div 3 = 56 \\7x = 56 \times 3 \\ 7x = 168 \\ x = 24$

Difference of First and Third number=

$4x - 2x \\ = 2x \\ 2 \times 24 = 48$

So, 48 is the correct answer.