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3 years ago

Fred completed 10 math problems. That is 40% of the number of math problems he has to do. How many math problems must he do?

Mathematics

2 answers:

GalinKa [24]3 years ago

7 0

Fred must complete 25 matg problems and so far of those 25 problems he has completed 10 math problems. Hope this helps!

Ivanshal [37]3 years ago

7 0

Answer: 10

the answer is 10

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Wildlife sanctuary has 38 species of birds.

lbvjy [14]

Firstly, solve 38C15.

Then solve 42C12.

Compare your answers.

The goal here is to see if 38C15 = 42C12.

Here is the formula:

nCr = n!/(r!(n - r)!

Go for it.

3 0

3 years ago

At the beginning of a basketball season, the panthers won 20 games out of 50 games. At this rate, how many games will they win i

Anton [14]

Answer:

They will win 48 games in a 120 game season.

Step-by-step explanation:

The team won 20 games out of 50; that is a 20:50 ratio, that is equal to x:120. x is the amount of games won in the 120 game season.

Set up the ratios like this:

$\frac{20}{50}$ = $\frac{x}{120}$

cross multiply the numerators and denominators to get this:

20*120 = 50x

solve for x:

2,400 = 50x

x = 48

8 0

3 years ago

When x = 5, the value of the expression –2(x – 10) is

nikitadnepr [17]

Answer:

The value of the expression at x=5 is 10

Step-by-step explanation:

The given expression is $-2(x-10)$

Let us simplify this expression.

Distribute -2 over the parentheses, we get

$-2x+20$

Now, substitute x = 5, we get

$-2(5)+20$

On simplifying, we get

$-10+20\\=10$

The value of the expression at x=5 is 10

8 0

4 years ago

Read 2 more answers

1. Determine a rule that could be used to explain how the volume of a

Eva8 [605]

Answer:

See explanation

Step-by-step explanation:

Solution:-

- We will use the basic formulas for calculating the volumes of two solid bodies.

- The volume of a cylinder ( V_l ) is represented by:

$V_c = \pi *r^2*h$

- Similarly, the volume of cone ( V_c ) is represented by:

$V_c = \frac{1}{3}*\pi *r^2 * h$

Where,

r : The radius of cylinder / radius of circular base of the cone

h : The height of the cylinder / cone

- We will investigate the correlation between the volume of each of the two bodies wit the radius ( r ). We will assume that the height of cylinder/cone as a constant.

- We will represent a proportionality of Volume ( V ) with respect to ( r ):

$V = C*r^2$

Where,

C: The constant of proportionality

- Hence the proportional relation is expressed as:

V∝ r^2

- The volume ( V ) is proportional to the square of the radius. Now we will see the effect of multiplying the radius ( r ) with a positive number ( a ) on the volume of either of the two bodies:

$V = C*(a*r)^2\\\\V = C*a^2*r^2$

- Hence, we see a general rule frm above relation that multiplying the result by square of the multiple ( a^2 ) will give us the equivalent result as multiplying a multiple ( a ) with radius ( r ).

- Hence, the relations for each of the two bodies becomes:

$V = (\frac{1}{3} \pi *r^2*h)*a^2$

$V = ( \pi *r^2*h)*a^2$

8 0

3 years ago

The proportion of U.S. births that result in a birth defect is approximately 1/33 according to the Centers for Disease Control a

Dafna11 [192]

Answer:

Probability that at least 490 do not result in birth defects = 0.1076

Step-by-step explanation:

Given - The proportion of U.S. births that result in a birth defect is approximately 1/33 according to the Centers for Disease Control and Prevention (CDC). A local hospital randomly selects five births and lets the random variable X count the number not resulting in a defect. Assume the births are independent.

To find - If 500 births were observed rather than only 5, what is the approximate probability that at least 490 do not result in birth defects

Proof -

Given that,

P(birth that result in a birth defect) = 1/33

P(birth that not result in a birth defect) = 1 - 1/33 = 32/33

Now,

Given that, n = 500

X = Number of birth that does not result in birth defects

Now,

P(X ≥ 490) = $\sum\limits^{500}_{x=490} {^{500} C_{x} } (\frac{32}{33} )^{x} (\frac{1}{33} )^{500-x}$

= ${^{500} C_{490} } (\frac{32}{33} )^{490} (\frac{1}{33} )^{500-490}$ + .......+ ${^{500} C_{500} } (\frac{32}{33} )^{500} (\frac{1}{33} )^{500-500}$

= 0.04541 + ......+0.0000002079

= 0.1076

⇒Probability that at least 490 do not result in birth defects = 0.1076

4 0

3 years ago