The x coordinate of Q would be 5.
In order to find this, first note that P and R are exactly 2 away from each other (-1 to -3 is two away).
Now, we know that Q is 3 times as far away from R as P is given the ratio at the beginning. Therefore we know it is 6 away from R (2 * 3 = 6).
Now we simply add 6 to the R value to get the Q value.
-1 + 6 = 5