[問題] GRE online practice-1 Q問題

[konil (Q仔)]

大家好:

請教大家GRE online practice-1 Q問題:
1. A rectangular game board is composed of identical squares arranged in a
rectangular array of r rows and r+1 columns. The r rows are numbered from 1
through r, and the r+1 columns are numbered from 1 through r+1. If r>10, which
of the following represents the number of squares on the board that neither in
the 4th row nor in the 7th columns? (看不懂題目)

1. r2-r (ANS)
2. r2-1
3. r2
4. r2+1
5. r2+r
*  2表示平方

2. If a<= b<= c<= d<= e<= 110 and the average of a, b, c, d, and e is100,
what is the least possible value of a?

0 20 40 60(ANS) 80


3.How many three-digit positive integers are there such that the three digits
are 3,4, and 8?

3 6(ANS) 9 15 96

本來想說這題是3*4*8=96, 個位數=6, 但題目還是不是很懂!

感謝大家!


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→ kaifrankwind: 3. 有多少個正三位數, 是由3,4,8這三個數字所組成?
→ kaifrankwind: 2. a可能的值中, 最小是多少?
→ kaifrankwind: 1. 一長方形的長寬分別是r, r+1. 若r大於10, 則下列
→ kaifrankwind: 哪個選項表示第4列與第7欄之外的所有方塊數?
→ kaifrankwind: (長方形由一堆相同的正方形所組成)
→ roy047      : 1.  r*(r+1)-r-(r+1)+1=r^2-r