Let, first integer is x.
Therefore, other two are x+1 , x+2 .
Now, mathematical expression of given conditions is :
4x + 3 = 3(x+2)
4x + 3 = 3x + 6
x = 3.
So, the consecutive numbers are 3 , 4 and 5.
Therefore, the middle integer is 4.
Hence, this is the required solution.