“It was less than $100 for the four of us, which is quite reasonable.”
You went to a restaurant with a group of friends, and now you're writing a review of in on a restaurant-review website. You're report this about how much your meal cost.
It was less than $100 for the four of us, which is quite reasonable.
Tell how much something cost and how many people shared that cost with this phrase:
The room was $250 a night for the two of us.
If the price is for only one person, use "each" instead:
Dinner was only 15 bucks each.
When you see the phrase "the four of us", you should be able to tell that:
There were 4 people in the group that went to the restaurant, including the writer.
The writer already mentioned how many people were in the group in an earlier sentence.
You can tell #2 because this phrase uses "the". English speakers use "the" when they think their audience will know what they're talking about.
Use this pattern to combine two ideas. For the example at top, the two ideas are:
It was less than $100 for the four of us. Less than $100 for the four of us is quite reasonable.
Here are a few more examples of how you can use "which":
We're planning a trip to Australia, which we've never been to. Eric's mother is coming to visit us, which is great.
A "reasonable" price is not too expensive. Use this when something isn't cheap, but you're happy with the price because you feel like you got a good value for the price. "Quite" and "extremely" are adverbs that people often use with "reasonable":
$400 is quite reasonable, considering how much use you'll get out of it. It's an extremely reasonable price.