=8
=87a + 5b = 8a
=87a + 5b = 8a5b = 8a - 7a
=87a + 5b = 8a5b = 8a - 7aa = 5b
=87a + 5b = 8a5b = 8a - 7aa = 5b\frac{5a+7b}{b}= \frac{5*5b+7b}{b} = \frac{25b+7b}{b}= \frac{32b}{b} =32
=87a + 5b = 8a5b = 8a - 7aa = 5b\frac{5a+7b}{b}= \frac{5*5b+7b}{b} = \frac{25b+7b}{b}= \frac{32b}{b} =32 b
=87a + 5b = 8a5b = 8a - 7aa = 5b\frac{5a+7b}{b}= \frac{5*5b+7b}{b} = \frac{25b+7b}{b}= \frac{32b}{b} =32 b5a+7b
=87a + 5b = 8a5b = 8a - 7aa = 5b\frac{5a+7b}{b}= \frac{5*5b+7b}{b} = \frac{25b+7b}{b}= \frac{32b}{b} =32 b5a+7b
=87a + 5b = 8a5b = 8a - 7aa = 5b\frac{5a+7b}{b}= \frac{5*5b+7b}{b} = \frac{25b+7b}{b}= \frac{32b}{b} =32 b5a+7b =
=87a + 5b = 8a5b = 8a - 7aa = 5b\frac{5a+7b}{b}= \frac{5*5b+7b}{b} = \frac{25b+7b}{b}= \frac{32b}{b} =32 b5a+7b = b
=87a + 5b = 8a5b = 8a - 7aa = 5b\frac{5a+7b}{b}= \frac{5*5b+7b}{b} = \frac{25b+7b}{b}= \frac{32b}{b} =32 b5a+7b = b5∗5b+7b
=87a + 5b = 8a5b = 8a - 7aa = 5b\frac{5a+7b}{b}= \frac{5*5b+7b}{b} = \frac{25b+7b}{b}= \frac{32b}{b} =32 b5a+7b = b5∗5b+7b
=87a + 5b = 8a5b = 8a - 7aa = 5b\frac{5a+7b}{b}= \frac{5*5b+7b}{b} = \frac{25b+7b}{b}= \frac{32b}{b} =32 b5a+7b = b5∗5b+7b =
=87a + 5b = 8a5b = 8a - 7aa = 5b\frac{5a+7b}{b}= \frac{5*5b+7b}{b} = \frac{25b+7b}{b}= \frac{32b}{b} =32 b5a+7b = b5∗5b+7b = b
=87a + 5b = 8a5b = 8a - 7aa = 5b\frac{5a+7b}{b}= \frac{5*5b+7b}{b} = \frac{25b+7b}{b}= \frac{32b}{b} =32 b5a+7b = b5∗5b+7b = b25b+7b
=87a + 5b = 8a5b = 8a - 7aa = 5b\frac{5a+7b}{b}= \frac{5*5b+7b}{b} = \frac{25b+7b}{b}= \frac{32b}{b} =32 b5a+7b = b5∗5b+7b = b25b+7b
=87a + 5b = 8a5b = 8a - 7aa = 5b\frac{5a+7b}{b}= \frac{5*5b+7b}{b} = \frac{25b+7b}{b}= \frac{32b}{b} =32 b5a+7b = b5∗5b+7b = b25b+7b =
=87a + 5b = 8a5b = 8a - 7aa = 5b\frac{5a+7b}{b}= \frac{5*5b+7b}{b} = \frac{25b+7b}{b}= \frac{32b}{b} =32 b5a+7b = b5∗5b+7b = b25b+7b = b
=87a + 5b = 8a5b = 8a - 7aa = 5b\frac{5a+7b}{b}= \frac{5*5b+7b}{b} = \frac{25b+7b}{b}= \frac{32b}{b} =32 b5a+7b = b5∗5b+7b = b25b+7b = b32b
=87a + 5b = 8a5b = 8a - 7aa = 5b\frac{5a+7b}{b}= \frac{5*5b+7b}{b} = \frac{25b+7b}{b}= \frac{32b}{b} =32 b5a+7b = b5∗5b+7b = b25b+7b = b32b
=87a + 5b = 8a5b = 8a - 7aa = 5b\frac{5a+7b}{b}= \frac{5*5b+7b}{b} = \frac{25b+7b}{b}= \frac{32b}{b} =32 b5a+7b = b5∗5b+7b = b25b+7b = b32b =32
2) 15 - 2 = 13 км/ч - скорость против течения,
3) 17 * 2 = 34 км по течению,
4) 13 * 3 = 39 км - против течения,
5) 34 + 39 = 73 км - расстояние за все время