Dimensional Analysis

A piston-engined dragster traveled 440 yd in 4.936 s at Ennis, Texas. Find the average speed of the dragster in miles per hour.
Here's my stragedy
440yd (3ft/1yd)= 1320ft(1mile/5280ft)=1320/5280= .25miles per hour in 4.936sec.
so,
4.936sec(1min/60sec)= .08226mins
.08mins(1hr/60mins)= .08/60=.10hr
so,
.25miles per hour in .10 hr... am I on the right track?

\(\displaystyle \frac{3600 \;\ \not{s}\not{e}\not{c}}{1 \;\ hr}\cdot \frac{\frac{1}{4} \;\ miles}{4.936 \;\ \not{s}\not{e}\not{c}}\)