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Express 0.52 in the form qpтАЛ, where p and q are integers and qюАа=0.
9052тАЛ
9953тАЛ
9950тАЛ
9952тАЛ
9952тАЛ
For a pure repeating decimal of the form 0.ab, the equivalent fraction is 99abтАЛ. Here, 0.52 becomes 9952тАЛ.
The repeating decimal is 0.52 (with a bar over 52), representing 0.525252...
x=0.pтАЛ=99...9pтАЛ┬а(where┬а9тАЩs┬аcorrespond┬аto┬аthe┬аlength┬аof┬аthe┬аrecurring┬аperiod)
For a pure repeating decimal of the form 0.ab, the equivalent fraction is 99abтАЛ. Here, 0.52 becomes 9952тАЛ.
Students often mistakenly divide by 90 (which is used for mixed recurring decimals like 0.ab) instead of 99.
Define the equation
Let x=0.52=0.525252...
x=0.525252...
Shift the decimal
Since two digits repeat, multiply by 102=100 to shift the decimal point two places to the right:
100x=52.525252...
Subtract the equations
Subtract the original equation x from 100x to eliminate the repeating part:
100xтИТx=52.525252...тИТ0.525252...
Solve for x
Simplify the resulting expression 99x=52 to find the fraction:
x=9952тАЛ
D is correct because applying the standard rule for converting pure recurring decimals to fractions, 0.52=9952тАЛ.
This concept is foundational for Number System problems. Remember that for any decimal with a bar over n digits, the denominator is a string of n nines.