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11Alexandr11 [23.1K]

3 years ago

15

If there are 9 showings of a film at the science at a total of 486 people saw the same film the same number of people at each sh

owing

1 answer:

a_sh-v [17]3 years ago

6 0

54 people saw the film at each showing

You might be interested in

1. Prove or give a counterexample for the following statements: a) If ff: AA → BB is an injective function and bb ∈ BB, then |ff

Fantom [35]

Answer:

a) False. A = {1}, B = {1,2} f: A ⇒ B, f(1) = 1

b) True

c) True

d) B = {1}, A = N, f: N ⇒ {1}, f(x) = 1

Step-by-step explanation:

a) lets use A = {1}, B = {1,2} f: A ⇒ B, f(1) = 1. Here f is injective but 2 is an element of b and |f−¹({b})| = 0., not 1. This statement is False.

b) This is True. If A were finite, then it can only be bijective with another finite set with equal cardinal, therefore, B should be finite (and with equal cardinal). If A were not finite but countable, then there should exist a bijection g: N ⇒ A, where N is the set of natural numbers. Note that f o g : N ⇒ B is a bijection because it is composition of bijections. This, B should be countable. This statement is True.

c) This is true, if f were surjective, then for every element of B there should exist an element a in A such that f(a) = b. This means that f−¹({b}) has positive cardinal for each element b from B. since f⁻¹(b) ∩ f⁻¹(b') = ∅ for different elements b and b' (because an element of A cant return two different values with f). Therefore, each element of B can be assigned to a subset of A (f⁻¹(b)), with cardinal at least 1, this means that |B| ≤ |A|, and as a consequence, B is finite.

b) This is false, B = {1} is finite, A = N is infinite, however if f: N ⇒ {1}, f(x) = 1 for any natural number x, then f is surjective despite A not being finite.

4 0

4 years ago

Find the surface area of the cylinder. radius of 6. height of 7.

Sauron [17]

Answer:

SA = 156π

Step-by-step explanation:

The formula for surface area of a cylinder is

SA = 2πr² + 2πrh where r is the base radius, and h is the height.

We are given r = 6 and h = 7. Plug in those values and evaluate...

SA = 2π(6²) + 2π(6)(7)

SA = 2π(36) + 2π(42)

SA = 72π + 84π

SA = 156π

3 0

4 years ago

Read 2 more answers

Habiendose organizado un bingo se ha recaudado $1900. Por la entrada de hombres $15 y mujeres $10 y se ha reportado una asistenc

aev [14]

Answer:

The number of men was $80$

The number of women was $70$

Step-by-step explanation:

The question in English is

Having organized a bingo has raised $1900. For the entrance of men $15 and women $10 and an attendance of 150 people has been reported. Determine the number of men and the number of women who participated in the bingo.

Let

x----> the number of men

y----> the number of women

we know that

$x+y=150$

$x=150-y$ -----> equation A

$15x+10y=1,900$ -----> equation B

substitute equation A in equation B and solve for y

$15(150-y)+10y=1,900$

$2,250-15y+10y=1,900$

$15y-10y=2,250-1,900$

$5y=350$

$y=70$

Find the value of x

$x=150-70=80$

therefore

The number of men was $80$

The number of women was $70$

3 0

3 years ago

What is the equation of a line, in general form, that passes through point (1, -2) and has a slope of 1/3.

Studentka2010 [4]

Hello,

y+2=1/3*(x-1) ==>3y+6=x-1==>x-3y-7=0

Answer C

8 0

3 years ago

Read 2 more answers

The diameter of a circle is 7 cm. Find the circumference to the nearest tenth

Anton [14]

Answer:38.5 cm

Step-by-step explanation:To find the radius divide 7 by 2 which is 3.52. Then multiply 3.5 by itself which is 12.253.

3 0

2 years ago