Re: [計量] 請教幾題
: 3. Three friends are playing a game in which each person simultaneously
: displays one of three hand signs: a clenched fist, an open palm, or
: two extended fingers. How many different combinations of the signs are
: possible?
: (A) 7
: (B) 9
: (C) 10
: (D) 12
: (E) 27 ANS:(C)
: (不是應該是3*3*3/3=9種嗎?)
不同人出同一個sign視為相同
H(3,3) = C(5, 3) = 10
: 4. column A column B
: --------------------- ----------------
: the number of 3-digit 5
: whole numbers whose
: sum of the digits is
: equal to 3. ANS:(A)
: (三位數一定比一位數大阿 這有什麼好比的...是我會錯意思嗎?)
column A: 所有位數相加總和等於3的三位數整數個數
: 5. Paul wants to put up a 120-feet hedge around three sides of his rectangular
: garden and leave a side unfenced. If the garden has the greatest area, how
: many square feet of the garden will Paul hedge around?
: (A) 1200 sq ft
: (B) 1800 sq ft
: (C) 2400 sq ft
: (D) 3000 sq ft
: (E) 3600 sq ft ANS:(B)
設長=x, 寬=y
2x+y = 120, 使xy為最大
xy = x(120-2x) = -2x^2 + 120x = -2(x-30)^2 + 1800
x = 30, xy有最大值1800
: 6. If two cards are drwan at random without replacement form a standard deck
: of 52 cards that contain four different suits of 13 cards each, which is
: the probability that both cards will be of a given suit?
: (A) 1/4
: (B) 3/13
: (C) 13/102
: (D) 1/13
: (E) 1/17 ANS:(E)
: (這題是在問2張牌都是特定花色的機率嗎? 我為什麼會算成4/17..................)
: 7. If x varies directly as y^2, and x=8 when y=2, what is the value when x=32?
: ^^^^^^^^^^^^^^^^^^^^^^^^^
: 是說y^2=ax這樣囉?
: 8. column A column B
: ----------------------- -------------------------
: The area of table-cloth The area of a table-cloth
: that overhangs a circular that overhangs a square square
: tabletop by 1 meter on all tabletop by 2 meter on all sides.
: sides.
: ANS:(D)
column A: 超出圓形桌沿1公尺的桌布面積
column B: 超出圓形桌沿2公尺的桌布面積
: (又是一個看不懂..............)
: 麻煩大家囉!
: 謝謝=)
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