2856:40=71,6
71,6 * 40 =2856
<span>19217:30 =63,9
</span>63,9 * 30 =19217
<span>81569:500 =163,138
</span>163,138*500 =81569
<span>(R+357)-288=491
</span>R+357=491+288
R+357=779
R=779-357
R=422
Ответ: 422
<span>(R+357)-326=491
</span>R+357=491+326
R+357=817
R=817-357
R=460
Ответ: 460
1) 39+18=57(я)-Всего выбыло
2) 65-57=8(я)-Осталось
Ответ:8 яхт осталось!
1) (1/12+1/6) : (3/8-1/4) = (1/12+2/12) : (3/8-2/8) = 3/12 : 1/8 =1/4 * 8/1 = 2
2) (1 - 4/9) : (1/3 -1/4) = 5/9 : (4/12 - 3/12) = 5/9 * 12/1 = 20/3 = 6 2/3
3) (1/3 -5/16) : (1/6-1/8) = (16/48 - 15/48) : (4/24 - 3/24) = 1/48 : 1/48 = 1
4) (5/7 - 2/3) : (4/9 - 5/12) = (15/21 - 14/21) : (16/36 - 15/36) = 1/21 : 1/36 =
= 1/21 * 36/1 = 36/21 = 12/7 = 1 5/7