Hi, i'm preparing for Olevels and i have some maths questions that i'm not sure how to do, i'd appreciate it if you could help.
1. The numbers 60 and 126, written as products of their prime factors:
60=2^2x3x5
126=2x3^2x7
a)Find the largest integer which is a factor of both 60 and 126.
b)Find the smallest integer which is an exact multiple of both 60 and 126.
How do i make use of the prime factors that the question provided?? I really don't get it...
2. What does 'upper bound' mean?
This came from a maths question that says something like "The length of a rectangle is 12cm, correct to the nearest centimeter. What is the upper bound for the length of the rectangle?". Does it mean like, what is the largest possible length of the rectangle before it was rounded off?
3. Three bus services operate from the same depot. The first service leaves at 10 minute intervals, the second at 15 minute intervals and the third at 25 minute intervals. All three buses leaves at the 8am, at what time does does the three buses depot together?
*** I think i know how to find the answer, but i'm not sure if there's a faster way of doing. I only know how to list down all the multiples of the numbers and check for the first one common multiply. But that would be a rather slow method isn't it??
P.S. so basically i have problems with lowest common multiple and highest common factor. Please help! Thanks!!!!
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