GMATprep

yaoyao99

1.
4^17 = (2^2)^17 = 2^34
2^34 - 2^28 = 2^28 x (2^6 - 1) = 2^28 x 63 = 2^28 * 7 * 3^2

2.
intersections: (0,4) and (y, 0)
4 * y' / 2 = 12 => y' = 6
slope is positive => y is below the x axis => y = -6

3.
1) J = 2 * 3 * 5 => J has 3 different prime factors (inconclusive)
2) K = 2^3 * 5^3 => K has 2 different prime factors (inconclusive)
1 + 2 => J has more different prime factors

4.
1) Inconclusive, no idea about the car's speed for the next 200 kms
2) (actual speed + 20) * (actual time - 1 hour) = 400 kms = actual speed * actual time
Can solve for actual time

B

[此贴子已经被作者于2006-5-30 15:12:04编辑过]