Question
Harry paid a total of Rs. 800 for a set of different
mock tests. How many of the mock tests cost Rs. 40? I. Each Mock Test costs either 25 or 40 II. More than 4 Mock Tests cost Rs. 40Solution
From I, we get Let number of mock tests for Rs. 25 be x And number of mock tests for Rs. 40 be y Then, 25x + 40 y = 800 5x + 8y = 160 X = 32 - 8y/5 Since x is the number of mock tests for Rs. 25, it has to be a positive integer Thus, y can take the values 0, 5, 10, 15, 20 According to statement II, more than 4 mock Tests cost Rs. 40. Values of y more than 4 are: 5,10,15 and 20. Thus, we cannot find out the exact number of mock tests costing Rs. 40.
Find the mean of the following observations:
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