问题 解答题

一个三位数,三个数位上的数字之和为24,十位上的数字比百位上的数字小2。如果这个三位数减去一个两个数位上的数字与原三位数百位上的数字相同的两位数所得的数仍是一个三位数,且此三位数的三个数位上的数字的顺序和原三位数的三个数位上的数字的顺序恰好颠倒,求原来的三位数。

答案

解:可设原三位数百位上的数字为x,则原三位数十位上的数字为(x-2),个位上的数字为24-x-(x-2)=26-2x,新三位数的百位上的数字为26-2x,十位上的数字为x-2,个位上的数字为x

依题意可列出方程同,得100x+10(x-2)+(26-2x)一(10x+x)=100(26-2x)+10(x-2)+x

解得:x=9

则x-2=7,26-2x=8

即原三位数为100×9+10×7+8=978

答:原来三位数为978。

阅读理解

If you love books, then“Three Cups of Tea”will be your favorite. It will take you on an adventure(冒险)to one of the highest mountains in the world. You will learn how the people and children there lived and how the writer, Greg Mortenson , helped build an education system.

While climbing K2 in Pakistan, one of the world’s most difficult mountains to climb, Greg Mortenson became ill and got lost. He got help in a small village. The people of the village took good care of him, feeding him and letting him sleep in a villager’s house. They also gave him their best food: sweet tea.

When Mortenson was fine, he found that the children of the village worked and studied outdoors. Their teacher came only three times a week and they didn’t have blackboards. They used sticks(枝条)to write on the ground.

The day he left the village, he told them he would come back and build a school. His school would have both boys and girls. Later on, he came back and helped build a school, so the kids were able to study in the classroom with real writing instruments.

That was in 1993. Today Mortenson is going to build 80 schools in Central Asia. He started a foundation(基金)called the Central Asia Institute to raise money for these schools. He has helped more than 18,000 girls receive education so far.

小题1:“Three Cups of Tea”is the name of a        .

A.club

B.teahouse

C.book

D.movie小题2:The following are what the people of the village did for Greg Mortenson EXCEPT         .

A.taking care of him and feeding him

B.taking him to the hospital

C.finding somewhere to let him sleep

D.giving him their best food小题3:From the passage we know that        had more chances to receive education in Pakistan mountains in the past.

A.boys

B.girls

C.the rich

D.the poor

单项选择题