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2 years ago

There are 12 boys in a class. If the boys make up 4/5 of the entire class, how many students are in the class?

Mathematics

2 answers:

Solnce55 [7]2 years ago

4 0

Answer:

15 students

Step-by-step explanation:

Let x = number of students in the class

students * fraction of boys = boys

x * 4/5 = 12

Multiply each side by 5/4

x * 4/5 (5/4) = 12*5/4

x =15

There are 15 students

Ksivusya [100]2 years ago

3 0

Answer:

15 students

Step-by-step explanation:

Step 1: Divide 12 by 4 because if 12 is 4/5, then to find 1/5 you have to divide 4/5 by 4 and 12 by 4

12/4=3

Step 2: Add 12+3 because 4/5+1/5=5/5

12+3=15

There are 15 students in the class, hope this helps!

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statuscvo [17]

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m1 = (-4 - 2)/(4 - 2) = -6/2 = -3
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3 years ago

Researchers wanted to see which species of lizard (A, B, or C) is most likely to survive a bacterial infection. So they infected

Slav-nsk [51]

Answer:

A) attached below

B) 0.61

C) 0.47

Step-by-step explanation:

Given data:

Total number of lizards infected = 38

Of the 15 species B lizards 40% survived

For specie C one more survived than died

Out of the 24 lizards that died 1/3 were species A

A) contingency table

attached below

B) Determine the proportion of these lizards in this study that were either specie A or Specie B

P ( A or B ) = ( 8 + 15 ) / 38 = 0.605 ≈ 0.61

C) determine the probability that specie C lizard did not study

P ( not surviving | C ) = 7 / 15 = 0.466 ≈ 0.47

7 0

2 years ago

A box contains cards bearing numbers from 6 to 70. If one card is drawn at random from the box, find the probability that it bea

777dan777 [17]

Answer:

a) 4/65 b) 13/65 c) 12/65 d) 19/65

Step-by-step explanation:

Probability is the likelihood or chance that an event might occur.

Probability = expected outcome of event/Total outcome of event

If a box contains cards bearing numbers from 6 to 70, the total outcome will be the total number present from 6 to 70 which is 65

a) The amount of one digit number we have are 4 i.e {6,7,8,9}. This will be our expected outcome in this case.

The probability that the number drawn bears a one digit number will be 4/65

b) For numbers divisible by 5, the numbers that are divisible by 5 from the number drawn are {10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70}

The total expected outcome in this case = 13

The probability that the number drawn is divisible by 5 = 13/65

c) For odd numbers less than 30, they are {7,9,11,13,15,17,19,21,23,25,27,29}

The total expected outcome in this case = 12

The probability that the number drawn are odd numbers less than 30 = 12/65

d) For composite number between 50 and 70, this are numbers that are within this range and they includes {51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69}

The total expected outcome in this case = 19

The probability that the number drawn are composite numbers between 50 and 70= 19/65

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3 years ago

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yaroslaw [1]

I hope this helps you