calculati a)84 de grade 25 min 42 sec-16grade 46min 25 sec
b)120grade 36min 15 sec - 67grade 15min 36 sec
c)68 grade 29 min 32 sec - 24 grade 37 min 53 sec



a)2×64grade 37 min 21 sec
b)2×18grade 54min 38sec
c)3×54grade 28min 54 sec
d)3×68grade 47min 56 sec​