Question

Question le

One parish has 5 rivers, anothe hou
7 rivers and a 3rd parnh hav 8 rivers
Of the river in the parisha there
one that flows through all
three parish?how many rivers are there in the three parishes

Answer 1

To find the total number of distinct rivers in the three parishes with one river flowing through all, we use the inclusion-exclusion principle, resulting in 18 distinct rivers.

Step-by-step explanation:

The student is asking how many rivers there are in three parishes if one river flows through all of them. To solve this, we use the principle of inclusion-exclusion. The first parish has 5 rivers, the second has 7, and the third has 8. Since one river flows through all three, it is being counted three times. Therefore, the total number of distinct rivers is 5 + 7 + 8 - 2 (since the one river that flows through all three is counted twice more than it should be).

The calculation goes as follows:

1. Add the number of rivers in all parishes: 5 + 7 + 8 = 20
2. Subtract the river that has been counted three times: 20 - 2 = 18

Hence, there are 18 distinct rivers in the three parishes.