Найдите х в пропорции: ((5/18 - 4/15):1/6 + 3 целых 14/15):0,8 х ------------------------------------------------- =

Упростим пропорцию:

1) (5/18 - 4/15) * 6 = 5 * 6/18 - 4 * 6/15 = 5/3 - 8/5 = 25/15 - 24/15 = 1/15;

2) 1/15 + 3 14/15 = 1/15 + (3 * 15 + 14)/15 = 1/15 + 59/15 = (1 + 59)/15 = 60/15 = 4;

3) 3 1/25 * 5/12 = (3 * 25 + 1)/25 * 5/12 = 76/25 * 5/12 = 76/60;

4) 2/3 * 1 3/8 = 2/3 * (8 + 3)/8 = 2/3 * 11/8 = 22/24 = 11/12;

5) 76/60 - 55/60 = 21/60 = 7/20;

6) 4 5/16 - 3 1/6 = (4 * 16 + 5)/16 - (3 * 6 + 1)/6 = 69/16 - 19/6 = 207/48 - 152/48 = 55/48;

Получим пропорцию:

4 : 0,8х = 7/20 : 55/48;

4 * 55/48 = 0,8 * х * 7/20;

х = 55/12 * 20/7 * 10/8;

х = 1375/84.