参考答案:

　　1.Correct Answer: 2160

　　Explanation:

　　First calculate how many seconds there are in a 24 hour period.

　　24 x 60 x 60 = 86400

　　Divide by 40 to find how many pictures = 2160

　　2.Correct Answer: 80

　　Explanation:

　　Since the big triangle is equilateral, angle BAC = 60, and x = 60/3 = 20

　　Now, since the angles of measure X divide the angle equally, the line segments from A to BC are also equal. This makes y the measure of one of a pair of equal angles of an isosceles triangle. So y = (180 - x)/2; y = 80

　　3.Correct Answer: 8

　　Explanation:

　　Since five puppies require one sack per week, 15 puppies require 3 sacks. So out of the five available, the puppies will use 3, leaving 2 for the dogs. One sack feeds four dogs, so 2 sacks will feed 8.

　　4.Correct Answer: 660

　　Explanation:

　　Let the numbers be x,y, and z

　　Follow the directions for each number: increase by 20 and multiply the result by 10. Then add the terms:

　　10(x + 20) + 10(y + 20) + 10(z + 20) = required sum

　　10x + 200 + 10y + 200 + 10z + 200 = 600 + 10(x + y + z)

　　Since x + y + z = 6; the sum = 600 + 60 = 660

　　5.Correct Answer: 1125

　　Explanation:

　　Factorize the number

　　4500 = 2 x 2250 = 2 x 2 x 1125

　　No need to go any further because 1125 is odd.

　　6.Correct Answer: 10

　　Explanation:

　　When opened out, the cylinder forms a rectangle of 12 x 8.

　　The straight line distance between A and B will be from a point on the long edge to a point on the opposite edge, such that the line forms the hypotenuse of a triangle height 8, and base half the circumference (=6). This is a 3-4-5 triangle, and the hypotenuse will be 10.

　　7.Correct Answer: 2

　　Explanation:

　　Speed = distance/time; time = distance/speed

　　Car M traveling at 60mph covers 10 miles in 10/60 hours.

　　In the same time, car N traveling at 48mph will cover 48 x 10/60 miles= 8

　　Car N will therefore still have 2 miles to travel.

　　8.Correct Answer: 10

　　Explanation:

　　There is one 3-symbol arrangement allowed using the first symbol.

　　Further arrangements can be made with the last symbol in the third place, and choosing any of the remaining three symbols for the first place and any of the same three symbols for the second place. This give 3 x 3 arrangements = 9

　　Along with the first possibility, this makes 10

　　9.Correct Answer: 3

　　Explanation:

　　To make both sides equal, the obvious thing to do is to substitute 3 for x

　　10.Correct Answer: 3

　　Explanation:

　　First rearrange the second equation to fit the form y = mx + c, where m = slope

　　We get y = (9/k) x - 6/k

　　Parallel lines have the same slope. From equation 1, slope = k

　　From equation 2, slope = 9/k . Equating the two slopes we get k = 9/k; k² = 9; k = 3