Converting 0 to 24V analog signal to 0 to 5V for ADC input?
Sounds right to me. I calculate that a 24V input will result in a 4.88V output. But since you are asking, I'm assuming this isn't what's actually happening. Is the voltage you are trying to measure provided by a low-impedance source? Otherwise, you will have to include that impedance as part of R1, or buffer the signal with an op-amp or such.