Recall that the previous hint stated that the magic number is 15×x, where x is a number between 1 and 10. specifically x is an even number between 1 and 10. try to guess the value of x.

15 x x is the given number and  find the value of x,
the hint is given here that the x is a number between 1 and 10,and x is an even number.
Now we know that the even number are 0,2,4,6,8,10,12 and so on. the even numbers between 1 and 10 are 2,4,6 and 8.
so, according to the information provided the value of x is may be 2,4,6 or 8.