Problem: three numbers are in the ratio 3 : 4 : 5 and their l . c . m . is 1800 . their h . c . f is ?
Rationale: "let the numbers be 3 x , 4 x and 5 x their l . c . m . = 60 x 60 x = 1800 x = 30 the numbers are 3 * 30 , 4 * 30 , 5 * 30 hence required h . c . f . = 30 answer is b"
annotated_formula: add(multiply(multiply(3, 5), const_100), multiply(4, 5))