We have been given that the weight of an object on the mars varies directly as the weight of the object on earth.
Let y be weight of an object on Mars and x be weight of an object on Earth.

We have been given that the weight of an object on Mars is 34 pounds and weight of the same object on Earth is 90 pounds.
Putting the given values in equation we get

Therefore, our equation now becomes

Now we have been given that the weight of an object on Earth is 135 pounds and we have to find the weight of the same object on Mars,
We have been given that

Putting the given values in our equation we get

Therefore weight of the object on Mars will be 51 pounds.