1. выполните действие а) 3/4 : 5/11 б) 6/7 : 12/35

1. а) 3/4 : 5/11 = 3/4 * 11/5 = 33/20;

б) 6/7 : 12/35 = 6/7 * 35/12 = 5/2;

в) 4 6/11 : 1 3/22 = (4 * 11 + 6)/11 : (1 * 22 + 3)/22 = 50/11 : 25/22 = 50/11 * 22/25 = 4;

г) 75 : 15/16 = 75 * 16/15 = 80;

д) 14/15 : 7 = 14/15 * 1/7 = 2/15;

2. 2/3 * х = 28; х = 28 * 3/2 = 42;

Стоимость за 1 кг пастилы 42 рубля.

3. а) 14/14 * b - 5/14 * b = (5 * 7 + 1)/7;

9/14 * b = 36/7;

b = 36/7 * 14/9 = 8;

б) 71/10 * с + 10/10 * с = 405/100 * 4/10;

81/10 * с = 81/50;

с = 81/50 * 10/81 = 1/5.

4. 1 5/7 * х + х = 76;

12/7 * х + 7/7 * х = 76;

х = 76 * 7/19 = 28 (подосиновиков);

76 - 28 = 48 (белоснежных грибов);

5. 3/8 * а = 72/100 * b;

а = 8/3 * 72/100 * b = 48/25 * b.