3/5 of a certain class left on a field trip. 1/3 of the students who stayed behind did not want to go on the field trip (all the others did want to go). when another vehicle was located, 1/2 of the students who did want to go on the field trip but had been left behind were able to join. what fraction of the class ended up going on the field trip?

11/15

Step-by-step explanation:

In this kind of problem, it is cool to always have a value for the total number of students. We can choose any arbitrary value for this. So let’s say the total number of students is 120.

Now we were told 3/5 left for the field trip. The number that left corresponds to 3/5 of 120 = 72 students. The number that didn’t go on the field trip is thus 120 - 72 = 48 students.

Now what do we know again? 1/3 of those who stayed behind didn’t want to go. The number that didn’t want to go is thus 1/3 of 48 = 16. The number that wanted to go but didn’t leave with the first batch is thus 48 - 16 = 32

Now, a bus came along and half of those who wanted to go but were left behind joined. This is equal to a value of 1/2 * 32 = 16

Now the question is what fraction of the class left for the field trip. All we need do is add the first batch to the second batch and divide the result by the total number of students. The addition of both yields = 72 + 16 = 88 students.

The fraction that left was thus 88/120 = 11/15

step-by-step explanation:

i found the life tables for the year 2012. 

life table of males at age 30. probability of dying between ages x and x+1

total population:  

29–30 . . . . . . . . . . . . 0.001030

30–31 . . . . . . . . . . . . 0.001061

males:  

29–30 . . . . . . . . . . . . 0.001420

30–31 . . . . . . . . . . . . 0.001448

white population

29–30 . . . . . . . . . . . . 0.001005

30–31 . . . . . . . . . . . . 0.001037

white males

29–30 . . . . . . . . . . . . 0.001372

30–31 . . . . . . . . . . . . 0.001399

non hispanic white population

29–30 . . . . . . . . . . . . 0.001083

30–31 . . . . . . . . . . . . 0.001116

non hispanic white males

29–30 . . . . . . . . . . . . 0.001477

30–31 . . . . . . . . . . . . 0.001503

jacob, non hispanic white male. 30 years old.

probability that jacob lives to be 30 years old. 

since the given probabilities are probabilities of dying, i think we simply subtract it from 1 to get the probability of living. we will use the probability of non hispanic white male.

                                          probability of living to be 30 y.o.

29 - 30 : 1 - 0.001477 = 0.998523

30 - 31 : 1 - 0.001503 = 0.998497