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Query: Twenty one identical balls are numbered 1 to 21. They are placed in a bag and two balls are selected without replacement. What is the probability that the numbers on both balls are less than 7?
Response: Click on the graphic for the solution...
Query: Given that y is inversely proportional to x2 and x=15 when y=2, find x when y=50.
Response: Take a close look at the solution below...
Query: How do I find the equation of this graph?
Response: You should record the coordinates of points along the graph and try to work out the unique relationship between x & y via the pattern which connects them.
Here, we have the points (12,1), (6,2), (4,3), (3,4), (2,6) & (1,12).
Notice, if you multiply the pair of coordinates each time you get the answer 12. So, the equation is xy=12 or y=12/x.
You could also have recognised this as a transformation of the reciprocal graph, y=1/x.
