150 x 12 = 1800
55 x 12 = 660
1800 + 660 + 45000 = 47,460
Answer:
x = 7
Step-by-step explanation:
Distribute the 2 on the right and the -1 on the left: 13 - 2x - 2 = 2x + 4 + 3x
Combine like terms on each side of the equation: 11 - 2x = 5x + 4
Add 2x to both sides, and subtract 4 from each side: 7 = 7x
Divide both sides by 7: x = 7
Try this solution:
let the unknown two-digits number be 'xy'.
Then it is possible to write any two-digit number as 10x+y, where x - the tens digit and y - the unit digit.
Using the rule described above the phrase 'the tens digit of a number is twice the units digit' may be written as x=2y.
Using the same rule the phrase 'if the digits are reversed, the new number is 36 is less than the original number' may be written as (10x+y)-(10y+x)=36.
These two equations may be resolved as system of two equations:

Check: the original number is 84, the new number is 48; difference is 84-48=36.
answer: 84