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想請問幾題GWD的解題方法 The sum of the first k positive integers is equal to k(k+1)/2. What is the sum of the integers from n to m, inclusive, where 0 < n < m ? Ans: m(m+1)/2-(n-1)n/2
In the xy-plane, line a and line b have the same slope. If the y-intercept of line a is –1, what is the y-intercept of line b ? (1) The x-intercept of line a is –1. (2) Line b passes through the point (10, 20). Ans: C On a certain transatlantic crossing, 20 percent of a ship’s passengers held round-trip tickets and also took their cars abroad the ship. If 60 percent of the passengers with round-trip tickets did not take their cars abroad the ship, what percent of the ship’s passengers held round-trip tickets? Ans: 50%
In the xy-plane, line n passes through the origin and has slope 4. If points (1, c) and (d, 2) are on line n, what is the value of c/d? Ans: 8 | 
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发表于 2009-7-13 16:16:00
