A puzzle that puzzled me

Tweet

There are 4 persons named one,two,five,ten. they want to cross a bridge with a lamp. Maximum two persons are allowed at a time to cross that bridge. the time taken by each person to cross the bridge is equivalent to their name, i.e. one takes 1 sec, two takes 2 seconds,five takes 5 seconds and ten takes 10 seconds to cross the bridge. if two people walk simultaneously then the time taken is the maximum of both,i.e if five and ten go together then it will take 10 seconds to cross the bridge. What is the lowest time in which all the four persons will cross the bridge? I got the answer 19 but the correct answer is 17 can anyone tell how is it possible?