I don't understand why the answer is a

But the question states that the gas bill INCREASED

Read the question stem again. B-E are all reasons to why the bill would increase. A is the only reason that answers the EXCEPT portion of the question stem.

But this doesn't make much of sense considering the fact that we are talking about Jimmy's gas bill going up in right after he got a new gas water heater and the choices given are talking about uncle moving in with him or the gas company
raising the bill just because jimmy has got new gas water heater. We can't just inject facts with are not given and consider those in my answer choices

If the new heater uses less gas it would not make the bill go up.
All other answer could make the bill go up.

I don't understand why a is the answer especially if there is an increase in the gas bill. In my understanding either the old gas heater was not efficient and did not use enough gas to get the job done, or the there an outside factor made the gas heater use more energy than usual.

But in the question it says his gas bill increased after the new water heater was installed.

We can assume that when the NEW heater was installed, it would be more efficient and the gas bill would be less expensive.

But it is MORE expensive. The question asks us to find the odd answer that does NOT help us figure out why it is more expensive. And two things affect how high his gas bill would be: how much gas is used (more gas=higher bill) and cost for gas (higher rate=higher bill)

B. it would be more expensive if his uncle moved in because they would use twice the gas (more gas)

C. If he starts doing laundry at home, he is using more gas than before (more gas)

D. If the gas company makes gas more expensive and he uses the same amount then the gas bill will be higher.

E. A cold winter forces him to use more gas to stay warm (more gas).

Now let's look at A. If the new water heater uses a smaller percentage (less gas) than the old water heater, would the gas bill go up or down? Surely we would expect it to go down (less gas is used). So this is the only answer that does not make it clear why the gas bill increases.

Hope this helped.
DS

I don't understand this answer

Oh I get it, the stem says that if all the answers are correct knowing they are a possibility for an increase in the bill EXCEPT ONE OF THE ANSWER IS NOT POSSIBLE. Got it!!

I don't get the 2nd question

Utilize process of elimination In this question and you'll find the answer. Look out for the choice that would not help explain why the gas bill increased. Answer A is perfect here as it provides evidence to show why the bill should have actually decreased. this goes against the conclusion drawn. This is the answer we're looking for