If 1234 = 55, 1632 = 93, 1525 = 76, 3424 = 67 then 6171 = ?

Question

if 3+4=21 , 5+6=55 , 2+7=18 then how much is 6+8=?

Answer 1

87
first digit - the sum of middle digits
second digit - the sum of digits at the ends

Answer 2

ANSWER ( 1+7),(6+1) That is 87

Answer 3

87

the first digit sum of middle numbers
the second digit sum of number at ends