# converting miles into inches from wolframalpha

I was creating a simple quiz. I noticed that wolframalpha converts 0.25 miles into 15800 inches while google converts it into 15840 inches. Is it a bug or did I make some miscalculation?

• If you use 1/4 miles instead of .25 miles you get 15840 inches in WA. – kglr Dec 7 '14 at 22:31
• @kguler any explanation for weird behaviour? – Santosh Linkha Dec 7 '14 at 22:32
• Santosh, not sure... Using .250 miles also gives the correct result (WolframAlpha["convert .250 miles to inches", {{"Result", 1}, "ComputableData"}]). – kglr Dec 7 '14 at 22:38
• WA knows about significant figures and google does not. Put 0.2500 into WA and you get improved precision – bobthechemist Dec 7 '14 at 22:38
• Using precision implied by significant figures the "correct" answer is 16000. And how come .250005 -> 15840 not 15840.3 ? – george2079 Dec 8 '14 at 18:33

Using exact numbers or higher precision numbers gives the result that matches google's output:

WolframAlpha["convert 1/4 miles to inches", {{"Result", 1}, "ComputableData"}]
(* 15840 in *)

WolframAlpha["convert .250 miles to inches", {{"Result", 1}, "ComputableData"}]
(* 15840 in *)


Another example:

WolframAlpha["convert 1/5 miles to inches", {{"Result", 1}, "ComputableData"}]
(* 12672 in *)

WolframAlpha["convert " <> # <> "miles to inches", {{"Result", 1}, "ComputableData"}] & /@
{".2", ".20", ".200", ".2000"}
(* {12700 in, 12700 in, 12670 in, 12672 in} *)