作者grassroots (阿根)
看板GRE
標題[計量] 幾題數學求解
時間Sat Sep 8 00:48:55 2018
1. For a nonnegative interger n, if the remainder is 1 when 2^n is divided by
3, then which of the following must be true?(多選)
A. n is greater than 0
B. 3^n=(-3)^n
C. 根號2^n is an integer
2. If y is inversely proportional to x and y is 15 when x=5, what is the
value of y when x=25?
我是算y:x=15:5=75:25 故y=75.
但答案是y=3, 請問是我哪邊理解錯了？
3. {a,b} represents the remainder when a is divided by b.
c and d are positive intergers with c<d.(比大小)
A: {c,d}
B: {d,c}
4. If p and q are primes greater than 2, which of he following must be true?
(多選)
A. p+q is even
B. pq is odd
C. p^2+q^2 is even
D. 4p-q is even
E. p/2+q/2 is even
5. 這題我真的有看沒有懂...
Pat drove from his home to school at 60 miles per hour. Returning over the
same route, there was a lof of traffic, and he was only able to drive at
40 miles per hour. If the return trip took 1 hour longer, how many miles
did he drive for the round trip? (填空)
先謝過板上高手了
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1F：推 wenwen0616 : 1.B,C 2.題目說成反比 15*5=3*25 3.A>B 4.ABC 5 09/09 12:25
2F：→ wenwen0616 : .80miles 09/09 12:25
3F：推 Jincheng56 : 第四題,大於二的質數一定是奇數 09/09 12:27
4F：→ Jincheng56 : a)奇加奇是偶 09/09 12:27
5F：→ Jincheng56 : b)奇乘奇是奇 09/09 12:27
6F：→ Jincheng56 : c)奇平方還是奇，同a 09/09 12:27
7F：→ Jincheng56 : d)4奇=偶，偶加奇=奇 09/09 12:27
8F：→ Jincheng56 : e)帶入13和17是奇 09/09 12:27
9F：推 bbbb0829 : 第二題題目是給反比 你答成"成正比"的答案了 09/09 14:53
10F：→ bbbb0829 : 反比的式子是 Y=常數/X -> XY=常數 這樣就可以解了 09/09 14:54
11F：推 bbbb0829 : 第三題是A D>C 所以 D/C = 值...小於C的數值 09/09 14:57
12F：→ bbbb0829 : 而 C/D = 0....C 答案就出來了 09/09 14:58
13F：推 bbbb0829 : 第五題 先假設去程所花時間為X小時,則回程為X+1 09/09 15:03
14F：→ bbbb0829 : 得到算式 X*60 = (X+1)*40 -> X = 2 小時 09/09 15:04
15F：→ bbbb0829 : 2小時乘以60 miles/H 得到單趟路程為120miles 09/09 15:05
16F：→ bbbb0829 : 再*2 就可以得到來回總路程為240 miles 09/09 15:06