Answer: B. 370/999
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Explanation:
Let x = 0.370370370...
The "370" block repeats forever, due to the horizontal bar up top.
Multiply both sides by 1000 so that the decimal point moves three spots to the right.
x = 0.370370370...
1000x = 1000*0.370370370...
1000x = 370.370370370...
Then notice both x and 1000x involve the *exact* same decimal string of "370" repeating forever. This perfect match lets us cancel the decimal portions out when we subtract, and allows us to isolate x to get some fraction of integers.
1000x - x = 370.370370370... - 0.370370370...
999x = 370
x = 370/999
You can use your calculator to confirm that 370/999 = 0.370370370...
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In fact, you can use your calculator to determine the following:
A) 37/100 = 0.37
B) 370/999 = 0.370370370...
C) 37/99 = 0.373737...
D) 37/9 = 4.1111111....
This allows us to see fairly quickly that choice B is the final answer and that we can rule out the others.
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Side note: your calculator may round the last digit by mistake.
