Multiply both sides by 8 (to undo the division of 8)
x/8 < 10
8(x/8) < 8*10
x < 80
So any number less than 80 will make the original inequality true. This applies to choices: C, D, E which are the final answers. These values are all less than 80.
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Alternatively we can plug in each value into the inequality to check them
Choice A
x/8 < 10
80/8 < 10
10 < 10
false; choice A is eliminated
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Choice B
x/8 < 10
96/8 < 10
12 < 10
false; choice B is eliminated
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Choice C
x/8 < 10
64/8 < 10
8 < 10
true; choice C is one of the answers
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Choice D
x/8 < 10
40/8 < 10
5 < 10
true; D is another one of the answers
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Choice E
x/8 < 10
32/8 < 10
4 < 10
true; choice E is another solution
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Choice F
x/8 < 10
88/8 < 10
11 < 10
false; choice F is eliminated
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Whichever method you end up using, the final answers are C, D, E
