57*207=11799 мин :60=197 ч 5 м : 24=192 суток 5 ч и 5 мин
№1.
3 7/9 + 5 1/6 = 3 14/18 + 5 3/18 = 8 17/18
8 7/16 + 3 3/10 = 8 70/160 + 3 48/160 = 11 118/160= 11 59/80
6 8/12 + 9 7/18 = 6 24/36 + 9 14/36= 15 + 38/36 = 16 2/36= 16 1/18
9 3/16 + 4 7/12 + 3 5/24 = 9 9/48 + 4 28/48 + 3 10/48= 16 47/48
№2.
8 3/4 - х = 3 5/16
х= 8 3/4 - 3 5/16 = 8 12/16 - 3 5/16
х= 5 7/16
проверим:
8 3/4 - 5 7/16 = 3 5/16
8 12/16 - 5 7/16 = 3 5/16
3 5/16 = 3 5/16
(х- 9 3/7 ) + 5 8/21 = 6 5/14
х - 9 3/7 = 6 5/14 - 5 8/21
х - 9 3/7 = 6 15/42 - 5 16/42
х - 9 3/7 = 41/42
х=41/42 + 9 3/7 = 41/42 + 9 18/42
х= 10 17/42
проверим:
(10 17/42 - 9 3/7 ) + 5 8/21 = 6 5/14
10 17/42 - 9 18/42 + 5 16/42 = 6 5/14
15 33/42 - 9 18/42 = 6 5/14
6 15/42 = 6 5/14
6 5/14 = 6 5/14
70:5=14 15*6=90
14*7=98 90-18=72
98-18=80 72:12=6
80:5=16 6+90=96
16+64=80 96:16=6
Ответ:80 Ответ:6
Х-искомое время
70,5+57х=56,75+62,5х
5,5х=13,75
<span>х=13,75/5.5=2,5ч</span>
2 3/4х+2 1/2х=5 1/4х 5 1/4х* 12=14 5 1/4х=14: 12 5 1/4х =1,16 х=0,22