Question

7th grade homework! Probability quick Check Please answer as many as you can/ want to

Answer 1

Number 9 is 36 because there are 18/40 who feel safe, so it multiplied would be 36. C

Answer 2

6)

There are 5 striped, 6 solid, 2 floral & 2 polka dot t-shirts.

So there are 15 t - shirts in all.

The probability of choosing a polka dot t-shirt is 2/15

The probability of choosing a striped t-shirt is 5/15 = 1/3

Hence the probability of choosing a polka dot t-shirt & then a striped t-shirt = 2/15 × 1/3 = 2/45

Option J) is the right answer  

7)

Number of bones = 4

Number of balls = 5

Number of neck belts = 3

Total quantity = 4 + 5 + 3 = 12

The probability of choosing a bone = 4/12 = 1/3

Now as one quantity is selected, the total quantity left now is 11.

The probability of choosing ball is  = 5/11  

Hence the probability of choosing a bone & then a ball is = 1/3 × 5/11 = 5/33

Option A) is the right answer

8)

Total number of students = 28+14 + 8 = 50

Probability of roller coaster = 28/50 = 14/25

Probability of carnival games =14/50 = 7/25

Probability of Live shows = 8/50 = 4/25

Now 2 times probability of live show = 2(4/25) = 8/25 which is not equal to probability of Roller coaster.

F is not true

As probability of roller coaster ride is more than carnival games.

G is also not true.

Now 2 times the probability of carnival games = 2 (7/25) = 14/25 = Probability of Roller coaster ride.

Hence H is true

Now 2 times the carnival games = 2(7/25) = 14/25 which is not equal to Probability of Carnival games

Hence J is also not true.

Option H) is the true statement.

9)

Here the number of people feeling unsafe is 12, feeling neutral are 10 and feeling safe are 18.

Total number of people is 40.

The probability of a person feeling safe is 12/40

Now for 80 people, the number of people feeling safe shall be 12/40(80) = 24

10)

Here the digits are 1,2,3,4,5,6,7

The digits which are prime are 2,3,5,7

So there are 4 prime digits

The number of non prime digits is 3

And there are 7 digits.

Hence the probability of not selecting a prime number is 3/7

Option F is the right answer.