2*3=36
36:3= 12
36:2=18
18*2=36
12*3=36
2)
(2 9/16 + 5,45 : 6 8/35) : 6 1/9 = 9/16,
1) 5,45 : 6 8/35 = 545/100 : 218/35 = 545/100 * 35/218 = 7/8,
2) 2 9/16 + 7/8 = 2 9/16 + 14/16 = 2 23/16 = 3 7/16,
3) 3 7/16 : 6 1/9 = 55/16 : 55/9 = 55/16 * 9/55 = 9/16,
4)
(10 1/7 - 3,48 * 75/116) : 31 4/7 = 1/4 (или 0,25),
1) 3,48 * 75/116 = 348/100 * 75/116 = 9/4 = 2 1/4,
2) 10 1/7 - 2 1/4 = 10 4/28 - 2 7/28 = 9 32/28 - 2 7/28 = 7 25/28,
3) 7 25/28 : 31 4/7 = 221/28 : 221/7 = 221/28 * 7/221 = 7/28 = 1/4 (или 0,25)
20101+(625-7x) = 20579
625-7х=20579-20101
625-7х=478
7Х=625-478
7Х=147. Х=147:7. Х=21
50*60=3000
Ответ:3000 метров она плавала