Answer: 34
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Step-by-step explanation:
The odd numbers show up half of the time, on average.
So if x is the number of rolls, then 0.5x is the number of times we expect an odd number to show up. Set this equal to 17 and solve for x.
0.5x = 17
x = 17/0.5
x = 34
If Mark rolled the cube 34 times, then about half of those rolls (0.5*34 = 17) he should expect to get an odd number.