Question

Can someone explain this tree diagram for me? I understand why it’s 0.7 and why it’s 0.3 but what I don’t understand why it’s 0.4 shouldn’t it be 0.1? Shouldn’t it be 0.5 instead of 0.2?

Answer 1

66% have graduated within five years.

Explanation:

It is given that 70% of freshmen went to public schools. Then the rest 30% i.e.,
`$ (30)/(100) = 0.3 $` should have gone to other schools.

Now, the number the freshmen in public schools is considered as 100% or 1.

60% of the freshmen from public schools have graduated means out of the total freshmen from public schools, 60% of them have graduated. That is why it is denoted as 0.6 and those not graduated as 0.4.

Note that 60% of total students have graduated.

Let us assume there were 100 students initially. Then 70 students went to public school. Number of students graduated = 60%

`$ \implies (60)/(100) * 70  = 42 $`

That is 42 students have passed from public school.

Now, the ones in other schools:

80% of them have graduated in other schools. That means out of total students 80% of them have graduated.

That means
`$ (80)/(100) * 30 = 24 $`

24 students from other schools have passed.

Therefore, totally 66 students have passed. i.e., 66 percent have passed.