Решить 1/3+(-2/9)+4/27+(-8/81)= 2/3+(-4/9)+8/27+(-16/81)= 3/4+(-5/8)+7/16+(-9/32)= 5/4+(-7/8)+9/16+(-11/32)=

1) =(27//81)+(12//81) = (27-18+12-8)/81 = 13/81 2) =54/81-36/81+24/81-16/81 = (54-36+24-16)/81 = 26/81 3) =24/32-20/32+14/32-9/32 = (24-20+14-9)/32 = 9/32 = 0.28125 4) =40/32-28/32+18/32-11/32 = (40-28+18-11)/32 = 19/32 = 0.59375

22+18=40км

120: 40=3ч

ответ: 3ч