题干

甲、乙两只装满硫酸溶液的容器,甲容器中装有浓度为8%的硫酸溶液600千克,乙容器中装有浓度为40%的硫酸溶液400千克.从两只容器中各取(  )千克的硫酸溶液,分别放入对方的容器中,才能使这两个容器中的硫酸溶液的浓度一样.

A:48  

B:208  

C:240

D:160

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答案(点此获取答案解析)

C

同类题5

阅读下列短文,从每题所给的 A、B、C 和 D 四个选项中,选出最佳选项。

    I owned my own piano company in my thirties. Once, I received a postcard saying, "Please bring me a new piano for my little granddaughter. It must be red mahogany.  I can pay $10 a month with my egg money." Of course, I could not see a new piano for $10 a month. No finance company would carry a contract (合同) with payments that small.

    For months, I ignored them but the postcards were constantly coming to me. Out of curiosity, I looked the old lady up: She lived in a one-room cabin(小屋)in the middle of a cotton field and her little granddaughter was barefoot and wearing a feed-sack dress.

    Finding a red mahogany piano on my little truck, I delivered it to her and told her I would carry the contract myself at $10 a month with no interest, and that would mean 52 payments. I was sure I had just thrown away a new piano. Incredibly, the payments came in, all 52 of them as agreed.

    Then one day after 20 years, I sat in the Holiday Inn having a drink, I heard the most beautiful piano music behind me. I looked around, and there was a lovely young woman playing a very nice grand piano. I moved to a table beside her. She smiled at me, and when she took a break, she sat down at my table.

    "Aren't you the man who sold my grandma a piano a long time ago?" It didn't ring a bell, so I asked her to explain.

    She started to tell me, and I suddenly remembered. My Lord, it was her, the little barefoot girl in the feed-sack dress!

    She told me her name was Elise and since her grandmother couldn't afford to pay for lessons, she had learned to play by listening to the radio. She said she had started to play in church, then in school, and had won many awards and a music scholarship. She had married an lawyer in Memphis and he had bought her that beautiful grand piano she was playing.

    Something else entered my mind. "Elise," I asked, "It's a little dark in here. What color is that piano?" "It's red mahogany," she said, "Why?"

    I couldn't speak.

    Did she understand the full meaning of the red mahogany? The unbelievable insistence of her grandmother on a red mahogany piano when no one in his right mind would have sold her a piano of any kind? I don't think so.

    But I did, and my throat tightened.