the weight of an object on venus varies directly with its weight on mercury. if an object weighing 45 kg on mercury weighs 108 kg on venus, how much does an object weigh on venus if it weighs 35 kg on mercury?

Y varies directly with x means y=kx, where k is constant. In this case Venus is y and Mercury is x. Find k by plugging in the first two values,
k= y/x
k= 108/45 = 2.4

Then using the second value for Mercury
y = kx
y = (2.4)(35)
y = 84

The object weighs 84 kg