Which one of these numbers is not like the others 25,16,49,63,81

Which expression is equivalent to 8(k + m) − 15(2k + 5m)?

During a bike challenge riders have to collect various colored ribbons each 1/2 mile they collect a red ribbon each eighth mile they collect a green ribbon and each quarter mile they collect a blue ribbion wich colors of ribion will be collected at the 3/4 markrer

Which expression is not a polynomial?