1)
2 : 3/5 + 3/5 : 2 + 1 1/2 : 6 + 6 : 1 1/2 = 2 * 5/3 + 3/5 * 1/2 + 3/2 * 1/6 + 6 * 2/3 = 10/3 + 3/10 + 1/4 + 4 = 200/60 + 18/60 + 15/60 + 4 = 4 233/60 = 7 53/60
2)
6 1/4 * 8 - 3 2/3 * 5 1/2 + 2 2/5 * 4 7/12 = 25/4 * 8 - 11/3 * 11/2 + 12/5 * 55/12 = 50 - 121/6 + 11 = 40 5/6
3)
2 1/2 * 48 - 3 2/3 : 1/18 + 5 5/12 : 7/36 = 5/2 * 48 - 11/3 * 18 + 65/12 * 36/7 = 120 - 66 + 195/7 = 81 6/7
4)
13 1/2 : 1 1/3 + 16 1/2 * 1 5/11 + 19 1/4 : 4/25 = 27/2 * 3/4 + 33/2 * 16/11 + 77/4 * 25/4 = 81/8 + 24 + 1925/16 = 162/16 + 24 + 1925/16 = 154 7/16
<span>135. 1 3/5 = 8/5. 216 : 8 x 5 = 135.</span>
12 будет))))))))())))))))))(
5/8 : х = 2,5 : 1/2
2,5х = 5/8 * 1/2
2,5х = 5/16
х = 5/16 : 2,5
х = 5/16 : 25/10
х = 5/16 * 10/25
х = 1/8 * 5/5
х = 1/8
1) 15:5=3 сек -за 1 фотографию
2) 48*3=144 сек-за 48 фотографий
Ответ:144 сегунды понадобится