let

W = the weight on the object

m = the mass of the object

the weight of an object varies directly with the mass of the object

W = k*m, where k is constant

an object whose mass is 9kg weighs 54N that is m = 9 kg and W = 54 N

54 = k*9

k = 54/9

k = 6

now the formula for the weight is

W = 9m

the weight of the object is W = 24 N for the mass we find

24 = 9m

9m = 24

m = 24/9

m = 2.67 kg approximately.