Question

a number is 56 greater than the average of its third , quarter and one twelfth. find it.

Answer 1

((1/3x +1/4x + 1/12x) /3) + 56 = x 

multiply both sides by 3 
1/3x + 1/4x + 1/12x + 168 = 3x 

multiply boths sides by 12 to get rid of the fractional components 

4x + 3x + x + 2016 = 36x 

add the x's and take away 2016 

8x = 36x - 2016 

x = 4.5x - 252 

take away 4.5 x 

-3.5x = -252 

x = 72 

check 

1/4x = 18 
1/3x = 24 
1/12x = 6 

average (18 + 24 + 6)/3 = 16 

16 + 56 = x = 72

Answer 2

Hey, sup!

Let the number be x.

As per the question,

1/3 of x= x/3.
1/4 of x= x/4.
1/12 of x= x/12.

x - (x/3 +x/4 +x/12)/3=56.

Taking LCM.

=>(3x-(x/3+ x/4+ x/12))/3=56.

=>3x-x/3-x/4-x/12=56×3.
Taking LCM

=> (36x-4x-3x-x)/12= 168.

=> 36x-8x= 168×12.

=>28x=168×12.

=>x=(168×12)/28

=>x=6×12.

So the number is 72.

Hope it helps.