r = number of reptiles on the endangered species list
2r = twice that number
2r < 127 since the 127 is more than twice the number of reptiles
Solve for r by dividing both sides by 2
2r < 127
r < 127/2
r < 63.5
If r is a positive whole number, then r could be anything from this set: {1, 2, 3, ..., 62, 63}
Unfortunately there isn't enough information to fully pin down what r is.
I would ask your teacher for further clarification.