A、$ 20. B、$ 22. C、$ 20.80. D、$ 21.20. B

W: I’m exhausted. It took me about three hours just to buy a few things.
M: What did you buy?
W: I bought a dozen cassettes.
M: How much did they cost you?
W: I bought them on sale. They were $ 20 a dozen.
M: Including tax?
W: No. I paid another $ 0.80 in tax.
M: So the tapes cost you $ 20.80.
W: Right. Only I had to take the subway to and from the store, so that cost me another $ 1.20.
M: So the cassettes really cost you $ 22 a dozen.
W: Right. Altogether I spent $ 22. What did you buy today?
M: A half-dozen cassettes.
W: You’re kidding!
M: No. I had the same idea you had. I saw an ad in this morning’s paper so I went down to buy them.
W: What did they cost you?
M: I bought them for $ 2 a piece, including tax.
W: So you spent $ 12 on six tapes.
M: Yes. And I bought them in the neighborhood so I spent only a few minutes shopping and I didn’t spend any more money on transportation.
W: But my tapes still cost a total of $ 2 less than yours.
M: Sure, only you spent $ 22 on a dozen 60-minute tapes and I bought a half-dozen 90 minute tapes for $ 12.
W: Oh. It sounds like you really did get a bargain. But let’s check out the quality of our tapes and find out if either of us really got a good deal.
M: We should have thought of that before we bought them.
W: True. But we didn’t.