Пусть весь путь - х
Тогда 0,5x = 3/10x + 4 1/2 км
-4 1/2 = 3/10x - 1/2x
-4 1/2 = (3-5)/10x
-4 1/2 = -2/10x
-9/2 = -2/10x
x = -9/2 : -2/10
x = -9/2 * -10/2
x = 90/4
x = 45/2
x = 22,5 км
1/5*2/500 = 1/5*1/250=1/1250=0.0008
(6 7/12 - 3 17/36) * 2,5 - 4 1/3 : 0,65 = 1 1/9
1) 6 7/12 - 3 17/36 = 6 21/36 - 3 17/36 = 3 1/9
2) 3 1/9 * 2,5 = 28/9 * 5/2 = 70/9
3) 4 1/3 : 0,65 = 13/3 * 100/65 = 20/3
4) 70/9 - 20/3 = 70/9 - 60/9 = 10/9 = 1 1/9