60x3=180<span> ч
</span>180+5=185 мин
<span>1)1/2+1/3(13/4+5/6*1/8)=
5/6 * 1/8 = 5/48
13/4 + 5/48 = 156/48 + 5/48 = 161/48
1/3 * 161/48 = 161/44
1/2 + 161/144 = 72/144 +161/144 = 233/144 = 1 89/144
</span><span>2)5/3*4/6+(8/6-5/3)=
</span><span>8/6 -5/3 = 8/6 -10/6 = - 2/6
5/3 * 4/6 = 20/18 = 10/9
10/9 + ( - 2/6) = 20/18 -6/18 = 14/18 = 7/9
</span><span>3)2/4-1/2(3/8+6/7*1/5= решаю как если скобка после 1/5
</span><span>6/7 * 1/5 = 6/35
3/8 +6/35 = 105/280 +48/280 = 153/280
1/2 * 153/280 = 153/560
2/4 - 153/560 = 280/560 -153/560 = 127/560
</span>
24 / 12 = 2 часа велосипедист был в пути
(9/21-1/21)*224/16-1/16=8/21*223/16=1/21*223/2=2223/42=5 целых 13/42