1) 10-7=3(м/с) - скорость (V) сближения
2) 30 : 3 = 10( сек)
Ответ: за 10 секунд собака догонит кошку
0,4 * 1/4 = 4/10*1/4 = 1/10 (=0,1),
1/8 * 1,6 = 1/8*16/10 = 2/10 = 1/5 (=0,2),
2/3 * 3/4 = 2/4 = 1/2 (=0,5),
3/7 * 14 = 3*2=6,
4/15 * 60 = 4*4 = 16,
4/11 * 4,4 = 4/11*44/10 = 16/10 = 1,6,
1/5 * 100 = 100/5 = 20,
0,9 * 1/9 = 9/10*1/9 = 1/10 (=0,1),
3/4 * 4/5 = 3/5 (=0,6),
11/16 * 16 = 11,
1/2 * 0,3 = 1/2*3/10 = 3/20 (=0,15),
9/11 * 99 = 81,
5/8 * 0,4 = 5/8*4/10 = 1/4 (=0,25),
0,7 * 6/7 = 7/10*6/7 = 6/10 = 3/5 (=0,6),
13/15 * 30 = 13*2=26
1/60,5/60=1/12,10/60=1/6,12/60=1/5,15/60=1/4,20/60=1/3,25/60=5/12,30/60=1/2,35/60=7/12,40/60=2/3,45/60=3/4,50/60=5/6