30 is added to 1/3 of a number. the results is double the number. What is the number?

Answer 1

30 + x/3 = 2*x
30 = 5x/6
x = 30*6/5
x = 36

Answer 2

30 + x/3 = 2x
90 + x = 6x
90 = 5x
x = 18

check:
1/3 of 18 = 6
30 + 6 = 36
which is double our number of 18