Personal Math Trainer

Three numbers between 80 and 100 are prime numbers. What numbers are they? Eight numbers between 31 and 41 are composite numbers

Flura [38]

83, 89, and 97 are three primes between 80 and 100.

The primes between 30 and 50 are 31, 37, 41, 43, and 47, all of which are odd. All other numbers between 30 and 50 are composite.

To mentally find 2*50*25, you could either first multiply 25 by 2, to get 50*50, which can easily be calculated as 2500, or you could multiply the 50 by 2, for a result of 100*25, which is clearly also 2500.

5 0

3 years ago

Calculate the approximate probability that at least 2 children have been diagnosed with ASD among the 200 selected children.

mixas84 [53]

Answer:

The approximate probability that at least 2 children have been diagnosed with ASD among the 200 selected children is

0.01 or 1%.

Step-by-step explanation:

Number of selected children = 200

The probability of no child been diagnosed with ASD = P(None) = 198/200 = 0.99

Therefore, the probability of at least two children been diagnosed with ASD = 1 - 0.99 = 0.01.

This is the same as:

If 2 children have been diagnosed with ASD,

therefore, the approximate probability that at least 2 children have been diagnosed is:

2/200 = 0.01. This value is equal to 1%.

The above are summed up in:

The probability of at least one = 1/200 = 0.05

Therefore, the probability of at least two = 0.05 * 2 = 0.01

b) Generally, to find the probability of at least one event happening, we calculate the probability of none and then subtract that result from 1. That is, P(at least one) = 1 – P(none). For two events happening, the sum of the probability of at least one in two places is deducted from 1 to get the probability of at least two.

4 0

3 years ago

⚠️⚠️⚠️⚠️BREAKING NEWS A METEOR IS COMING DIRECTLY TOWARDS EARTH THEY ONLY WAY TO STOP THIS METEOR IS BY ANSWERING THIS QUESTION

8090 [49]

The relation {(-1 , 3), (4 , 2), (-1 , 5)} is not a function ⇒ 2nd

Step-by-step explanation:

Let us revise the meaning of relation and function

The relation is a set of inputs and outputs
A function is a relation with one output for each input, that means every x has only one y
Ex: {(2 , 3) , (-1 , -2) , (3 , 2)} is a function because 2 has only 3 , -1 has only -2 and 3 has only 2, {(1 , 7) , (2 , -4) , (1 , -3)} is not a function because 1 has 7 and -3

The relation is a function if and only if every x has only one y

In {(0 , 0), (1 , 0), (2 , 0)}

∵ x = 0 has y = 0

∵ x = 1 has y = 0

∵ x = 2 has y = 0

∴ Every x has only one y

∴ {(0 , 0), (1 , 0), (2 , 0)} is a function

In {(-1 , 3), (4 , 2), (-1 , 5)}

∵ x = -1 has y = 3

∵ x = 4 has y = 2

∵ x = -1 has y = 5

∴ x = -1 has y = 3 and 5

∴ Not every x has only one y

∴ {(-1 , 3), (4 , 2), (-1 , 5)} is not a function

In {(1 , 2), (3 , -5), (-1 , 7)}

∵ x = 1 has y = 2

∵ x = 3 has y = -5

∵ x = -1 has y = 7

∴ Every x has only one y

∴ {(1 , 2), (3 , -5), (-1 , 7)} is a function

In {(7 , -1), (3 , -2), (5 , -2)}

∵ x = 7 has y = -1

∵ x = 3 has y = -2

∵ x = 5 has y = -2

∴ Every x has only one y

∴ {(7 , -1), (3 , -2), (5 , -2)} is a function

The relation {(-1 , 3), (4 , 2), (-1 , 5)} is not a function

Learn more:

You can learn more about the relations and functions in brainly.com/question/10570041

#LearnwithBrainly

6 0

3 years ago

Lake Michigan's volume is approximately 1,180 cubic miles and its surface area is approximately 14,332,090 acres. The 2015 water

galben [10]

Answer:

a.) depth of the lake = (volume of the lake) / area of lake

= 173,693,585,360,000 / 624,305,840,400 = 278.22 feet

b.) 11 inches = 0.9167 feet

Water gained in cubic feet gained by the lake

= 624,305,840,400 $\times$ 0.9167

= 572,282,434,719.5 cubic feet

c.) the percentage change in the lake volume over that year

= 572,282,434,719.5 cubic feet / 173,693,585,360,000 cubic feet

= 0.0033

= 0.33%

Step-by-step explanation:

i) acres to square feet : 1 acre = 43560 square feet

therefore 14,332,090 acres = 624,305,840,400 square feet

ii) 1 mile = 5280 feet

1 cubic mile = 5280 $\times$ 5280 $\times$ 5280 = 147,197,952,000 cubic feet

therefore 1180 cubic miles = 173,693,585,360,000 cubic feet

a.) depth of the lake = (volume of the lake) / area of lake

= 173,693,585,360,000 / 624,305,840,400 = 278.22 feet

b.) 11 inches = 0.9167 feet

Water gained in cubic feet gained by the lake

= 624,305,840,400 $\times$ 0.9167 = 572,282,434,719.5 cubic feet

c.) the percentage change in the lake volume over that year

= 572,282,434,719.5 cubic feet / 173,693,585,360,000 cubic feet

= 0.0033

= 0.33%

7 0

4 years ago

Can you help me pleeeeaaassee??

melamori03 [73]

Error 1: DT / TS × CT / TR which is the first error. We can fix the error by writing the correct equation RT / TD = ST / TC, Error 2: The second error is 7 / 16 × (x - 1) / 14 and we can fix the error by writing the equation 14 / 7 = 16 / (x - 1), Error 3:The third error is the value of x and we can find the correct value of x from the equation 14 / 7 = 16 / (x - 1) and the value of x is 9.

Given: The diagram is given and we need to find the errors and then fix them. Also ΔTSR ≈ ΔTCD

Let's solve the given question:

Given that ΔTSR ≈ ΔTCD

So we know by the properties of the similarity that if two triangles are similar then the ratio of their corresponding sides is equal.

So, ΔTSR ≈ ΔTCD

=> RT / TD = ST / TC

=> 14 / 7 = 16 / (x - 1)

In the question, we can observe that the given side ratio is DT / TS × CT / TR which is the first error. We can fix the error by writing the correct equation RT / TD = ST / TC.

The second error is 7 / 16 × (x - 1) / 14 and we can fix the error by writing the equation 14 / 7 = 16 / (x - 1).

The third error is the value of x.

We can find the correct value of x from the given equation:

14 / 7 = 16 / (x - 1)

=> 2 = 16 / (x - 1)

Multiplying both sides by (x - 1):

(x - 1) × 2 = 16 / (x - 1) × (x - 1)

=> 2(x - 1) = 16

Multiplying both sides by 1 / 2:

2(x - 1) × 1 / 2= 16 × 1 / 2

=> x - 1 = 8

Adding 1 on both sides:

x - 1 + 1 = 8 + 1

x = 9

Therefore x = 9.

Hence the errors are:

Error 1: DT / TS × CT / TR which is the first error. We can fix the error by writing the correct equation RT / TD = ST / TC

Error 2: The second error is 7 / 16 × (x - 1) / 14 and we can fix the error by writing the equation 14 / 7 = 16 / (x - 1).

Error 3:The third error is the value of x and we can find the correct value of x from the equation 14 / 7 = 16 / (x - 1) and the value of x is 9.

Know more about "similar triangles" here: brainly.com/question/14366937

#SPJ9

8 0

2 years ago