##0.0335## ##(km)/h##
We need to convert ##75## ##(mi)/h## into ##(km)/h##
Cancel the hours in the denominator
##rarr75 (mi)/h*(1h)/(3600s)##
(as ##1## hour is ##3600s##)
##rarr75 (mi)/cancelh*cancel(1h)/(3600s)##
##rarr75 (mi)/(3600s)##
Cancel the miles in the numerator
##rarr75 (mi)/(3600s)*(1.609km)/(1m)##
(as ##1## mile is ##1.609km##)
##rarr75 cancel(mi)/(3600s)*(1.609km)/cancel(1mi)##
##rarr75 (1.609km)/(3600s)##
##color(green)(rArr0.0335(km)/s##
watch this video for another example