Answer:
5 (Answer A)
Explanation:
From the diagram we know that 2x - 6 + 1 + x - 4 must equal 18.
Then 2x - 6 + 1 + x - 4 = 18. Combining like terms, we get:
3x - 5 - 4 = 18, or 3x - 9 = 18
Then 3x = 27, and so x must be 9.
Then the length of RS is 9 - 4 = 5 (Answer A)