Math Olympiad 5( Week 26 Mid-Term Exam) 1. If a♣b = |a − 2b|, what is the value of (6♣3)♣5? 2. If a♠b = a2 − ab + b2, what is the value of (5♠1)♠4? 3. If a♥b = a + ab + b2, what is the value of (4♥3)♥2? 4. Josh is 5 times the age of Hillary who is 3 years older than Rene. If the total age of the three is 25, how old is Rene? 7. If a⊛b = a2 − 2ab + b2, which of the following has the greatest value? 8. There are 24 hours a day, 60 minutes in an hour and 60 seconds in a minute. There are even smaller time units, such as millisecond (10 −3 second), microsecond (10 −6 second), nanosecond (10 −9 second). How many seconds are in 1 hour 12 minutes? 9. If 3 days before yesterday was Monday, what day of the week will it be 20 days from today? 10. There are 12 triangles. Each triangle has exact one shared side with another triangle. How many sides are there in total? 11. There are 6 math exams during the semester. Steve has taken 5 exams so far and the scores were 91, 84, 86, 97, and 82. What will Steve need to score on his final math exam to have an average score of 86 for the semester? 12. Using digits 1, 2, 3, 4, 5, 6, 7, and 8, how many different 3-digit numbers can you make if no digit can be used more than once within a number? 13. Using a die(a cube with number of 1 to 6), what is the probability of throwing a 3, 4 and 5 in the order? 14. The product of 5 consecutive odd numbers must be divisible by: 15. What is the least common multiple (LCM) of 3, 4, 5, and 6? 16. A spinner shown in the diagram has 9 equal sections. The probability of the pointer falling into each section is the same (Assume the pointer will never fall on a line between two sections). What is the probability that the pointer falls on an odd number?
17. A spinner shown in the diagram has 8 equal sections. The probability of the pointer falling into each section is the same (Assume the pointer will never fall on a line between two sections). What is the probability that the pointer falls on a number that is a prime?
18. If 10x is deducted by 12y, and the difference is then multiplied by , which of the following is the result? 19. Three consecutive multiples of 15 have a sum of 405? What is the middle number among the three numbers? 20. A complete cycle of a traffic light takes 45 seconds with light in green for 25 seconds, amber for 5 seconds, and red for 15 seconds. What is the probability that the light will NOT be green? |