Question- GRE- Math

[abohammed]

Hi,

Guys, 

in page 333 from the official GRE guide book

problem (16)

if(1/(2^11 * 5^17) is expressed as a terminating decimal, how many nonzero digits will be the decimal have?

The correct answer is "Two"

I know how to reach (1/5^6 * 10^-11) easily.

but the question is how to know the number of digits easily without using calculator?

Thanks,

 

Edited September 10, 2015 by abohammed

[abohammed]

Just saw Magoosh video 

https://youtu.be/oJXTJn4pN6c

I got the idea

Thanks.

Edited September 10, 2015 by abohammed