Consider the following premises. For all y, y will not climb a mountain. For all y, if y climbs a mountain, then y is an office clerk. There is at least one y for which y is an office clerk if and only if y will drive a car. For all y, if y were an office clerk, then y is climbing a mountain. Can we infer the following from them? For all y, y will drive a car.
 From the fact that for all y, if y climbs a mountain, then y is an office clerk, and that for all y, if y were an office clerk, then y is climbing a mountain we can infer that for all y, y will climb a mountain if and only if y is an office clerk. From the fact that for all y, y will climb a mountain if and only if y is an office clerk, and that for all y, y will not climb a mountain we can infer that for all y, y is not an office clerk. Finally, from the fact that there is at least one y for which y is an office clerk if and only if y will drive a car, and that for all y, y is not an office clerk we can infer that there is at least one y for which y will not drive a car, which contradicts that For all y, y will drive a car. Therefore, the answer is no.