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3 years ago

Zack and tia played chess for 50 minutes they put the chess board away at 11:20 when did they start

1 answer:

6 0

10:30 because an hour before 11:20 is 10:20, but it was only 50 minutes, so add 10 minutes to 10:20 , and there you have it, 10:30.

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Can someone pls help need it ASAP and can you pls explain in full detail how to do it

GenaCL600 [577]

Answer:

x= 1 , y=4

Step-by-step explanation:

x-y= -3 => Equation 1

x+5y= 21 => Equation 2

Substitution Method:

Substitute Equation 1=>

x=y-3 <= Equation 3

Put x=y-3 in Equation 2:

x+5y=21

( y-3)+5y=21

y-3+5y=21

6y-3=21

6y=21+3

6y=24

y=24÷6

y=4

Put y=4 in Equation 1:

x-y= -3

x-4=-3

x=4-3

x=1

Hope this helps :)

8 0

2 years ago

Read 2 more answers

May someone help me with this equation, please 95=20x + 5

arsen [322]

Answer:

The answer is 9/2 or decimal form is 4.5 i gave you the work in the screenshot below hope it helps :)

Step-by-step explanation:

6 0

2 years ago

A=1/2 (a+b)h work out A if a=2 b=7 h=3

BartSMP [9]

Step-by-step explanation:

A =1/2(a+b)h

1/2(2+7)3
1/2×27
13.5

hope it helps.

6 0

2 years ago

Richard has just been given an l0-question multiple-choice quiz in his history class. Each question has five answers, of which o

myrzilka [38]

Answer:

a) 0.0000001024 probability that he will answer all questions correctly.

b) 0.1074 = 10.74% probability that he will answer all questions incorrectly

c) 0.8926 = 89.26% probability that he will answer at least one of the questions correctly.

d) 0.0328 = 3.28% probability that Richard will answer at least half the questions correctly

Step-by-step explanation:

For each question, there are only two possible outcomes. Either he answers it correctly, or he does not. The probability of answering a question correctly is independent of any other question. This means that we use the binomial probability distribution to solve this question.

Binomial probability distribution

The binomial probability is the probability of exactly x successes on n repeated trials, and X can only have two outcomes.

$P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}$

In which $C_{n,x}$ is the number of different combinations of x objects from a set of n elements, given by the following formula.

$C_{n,x} = \frac{n!}{x!(n-x)!}$

And p is the probability of X happening.

Each question has five answers, of which only one is correct

This means that the probability of correctly answering a question guessing is $p = \frac{1}{5} = 0.2$

10 questions.

This means that $n = 10$

A) What is the probability that he will answer all questions correctly?

This is $P(X = 10)$

$P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}$

$P(X = 10) = C_{10,10}.(0.2)^{10}.(0.8)^{0} = 0.0000001024$

0.0000001024 probability that he will answer all questions correctly.

B) What is the probability that he will answer all questions incorrectly?

None correctly, so $P(X = 0)$

$P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}$

$P(X = 0) = C_{10,0}.(0.2)^{0}.(0.8)^{10} = 0.1074$

0.1074 = 10.74% probability that he will answer all questions incorrectly

C) What is the probability that he will answer at least one of the questions correctly?

This is

$P(X \geq 1) = 1 - P(X = 0)$

Since $P(X = 0) = 0.1074$ , from item b.

$P(X \geq 1) = 1 - 0.1074 = 0.8926$

0.8926 = 89.26% probability that he will answer at least one of the questions correctly.

D) What is the probability that Richard will answer at least half the questions correctly?

This is

$P(X \geq 5) = P(X = 5) + P(X = 6) + P(X = 7) + P(X = 8) + P(X = 9) + P(X = 10)$

In which

$P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}$

$P(X = 5) = C_{10,5}.(0.2)^{5}.(0.8)^{5} = 0.0264$

$P(X = 6) = C_{10,6}.(0.2)^{6}.(0.8)^{4} = 0.0055$

$P(X = 7) = C_{10,7}.(0.2)^{7}.(0.8)^{3} = 0.0008$

$P(X = 8) = C_{10,8}.(0.2)^{8}.(0.8)^{2} = 0.0001$

$P(X = 9) = C_{10,9}.(0.2)^{9}.(0.8)^{1} \approx 0$

$P(X = 10) = C_{10,10}.(0.2)^{10}.(0.8)^{0} \approx 0$

$P(X \geq 5) = P(X = 5) + P(X = 6) + P(X = 7) + P(X = 8) + P(X = 9) + P(X = 10) = 0.0264 + 0.0055 + 0.0008 + 0.0001 + 0 + 0 = 0.0328$

0.0328 = 3.28% probability that Richard will answer at least half the questions correctly

8 0

3 years ago

A sledgehammer weighs 18 pounds on Earth and 4 pounds on the planet Namar.

Advocard [28]

It would weight 18lbs i believe

8 0

2 years ago

Read 2 more answers