What is 24 120mm on aps c in full frame?

24-120mm on APS-C gives the view of 36-180mm on full frame.

The same view on every common format:

• Medium format (44 x 33): 46-228mm
• Full frame: 36-180mm
• APS-C (yours): 24-120mm
• APS-C (Canon): 22-112mm
• Micro Four Thirds: 18-90mm
• 1-inch: 13-67mm
• 1/1.3-inch: 10-50mm
• 1/1.7-inch: 7.8-39mm
• 1/2.3-inch: 6.4-32mm

Crop factors are by the sensor diagonal, rounded as they're usually quoted; a format with a different shape (4:3 against 3:2) frames a little differently across the width. More in the focal length converter.

Computed from the sensor sizes, not written by a model.