tailieunhanh - sat 6 full tests phần 9

Tham khảo tài liệu 'sat 6 full tests phần 9', ngoại ngữ, ngữ pháp tiếng anh phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 22. How many positive double-digit numbers are there where both the tens and the units digits are prime numbers A 15 B 25 C 35 d 45 E 55 The best answer is B. The possible prime digits are 1 2 3 5 and 7. The numbers that can be put together are 11 22 33 55 77 12 13 15 17 21 23 25 27 31 32 35 37 51 52 53 57 71 72 73 and 75. Altogether we have 25 numbers and so the right answer is B. 23. A2 A A-3 If A2 A and A-3 lie on a number line in the order show in the figure above which of the following can be a value of A A -4 B c 0 D e 2 The best answer is D. The only way that A2 is smaller than A and that A-3 is larger than A is if A is a positive fraction. Take answer D for example A . A2 1 16 and A-3 64 and so this answer is good. 24. A snake crawled for three minutes. In the first minute the snake traveled 65 feet which was 30 farther than it traveled in the second minute. In the third minute the snake traveled at a speed of 5 feet per second. What is the total distance that the snake traveled in feet A 385 b 415 C 460 d 500 e 525 The best answer is B. In the first minute it traveled 65 feet. In the second minute it traveled X feet X 65 X 65 50 feet. In the third minute it traveled 5 x 60 300 feet. The total distance is 65 50 300 415 feet. 25. Two birds are flying towards one another. The first bird is traveling at a speed of 40 mph which is 25 faster than the second bird. If the distance between the birds is 20 miles how long will it takes the birds to meet In minutes A 35 B 30 C 25 D 20 E 15 The best answer is D. The speed of the second bird is X X 40 X 40 32 mph. In order to find the time it will take the birds to meet divide the total distance by the sum of the bird s speeds 24 40 32 24 72 1 3 hour which is 20 minutes and so the best answer is D. Chapter 2 1. The total weight of John and his brother is 180 kilograms. If John s weight is 15 Kilograms more than half of his brothers weight what is the differences .