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标题: gwd 26-8 [打印本页]

作者: pimplekid 时间: 2006-5-27 08:20
标题: gwd 26-8

Q8:

Which of the following fractions has a decimal equivalent that is a terminating decimal?

A. 10/189

B. 15/196

C. 16/225

D. 25/144

E. 39/128

作者: yaoyao99 时间: 2006-5-27 11:38
A: 189 = 3^4 * 7
B: 196 = 2^4 * 11
C: 225 = 5^2 * 3^2
D: 144 = 3^2 * 2^4
E: 128 = 2^7

39/128 = 39 * (0.5)^7 (limited number of decimal numbers)

E

作者: pimplekid 时间: 2006-5-31 19:36

谢谢斑竹！

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