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3 years ago

When I multiply 9x9 how would I go about counting by 9s?

Mathematics

1 answer:

11111nata11111 [884]3 years ago

5 0

Answer:

If you're looking for a shortcut, I usually find the number 1 less than what you are multiplying 9 by, this case 8, and then add a number that gets to 9.

So 9x6 would be:

5+4=9

Step-by-step explanation:

When multiplying by 9s the product's two numbers added together =9.

Sorry if this is confusing. Hope this helps though.

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6 x £20 notes, 7 x £5 notes

Step-by-step explanation:

6 x £20 = £120

7 x £5 = £35

£130 + £35 = £155

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Nicole bought a piece of property for $12,000. She sold it for $15,000. What is the percent of increase? <br> A. 20% B. 1

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4 years ago

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20 points!! What is the value of p? 10p+5= 18p–6/2 A–8 B–1/8 C4 D8

Artemon [7]

The answer is D.) 8

Explanation: 10p+5= 18p–6/2

Subtraction Property of equality states that you subtract the same number from both sides of an equation.

Subtract 10p from both sides of an equation

10p+5-10p = 18p-62-10p

Simplify:

5 = 8p -62

Addition Property of equality states that you add the same number from both sides of an equation.

Add 62 to both sides of an equation:

5+62 = 8p -62 +62

Simplify:

67 = 8p

Division Property of equality states that you divide the same number from both sides of an equation.

Divide by 8 in equation [3] ;

Simplify;

p = 8.375 ≈ 8 (approx)

Therefore, the value of p is, 8

Hope this helps :) sorry if wrong and sorry about confusion.

8 0

3 years ago

Waiting on the platform, a commuter hears an announcement that the train is running five minutes late. He assumes the arrival ti

natima [27]

Answer:

D. 91%

Step-by-step explanation:

Conditional Probability

We use the conditional probability formula to solve this question. It is

$P(B|A) = \frac{P(A \cap B)}{P(A)}$

In which

P(B|A) is the probability of event B happening, given that A happened.

$P(A \cap B)$ is the probability of both A and B happening.

P(A) is the probability of A happening.

In this question:

Event A: Less than 15 minutes.

Event B: Less than 10 minutes.

We are given the following probability distribution:

$f(T = t) = \frac{3}{5}(\frac{5}{t})^4, t \geq 5$

Simplifying:

$f(T = t) = \frac{3*5^4}{5t^4} = \frac{375}{t^4}$

Probability of arriving in less than 15 minutes:

Integral of the distribution from 5 to 15. So

$P(A) = \int_{5}^{15} = \frac{375}{t^4}$

Integral of $\frac{1}{t^4} = t^{-4}$ is $\frac{t^{-3}}{-3} = -\frac{1}{3t^3}$

Then

$\int \frac{375}{t^4} dt = -\frac{125}{t^3}$

Applying the limits, by the Fundamental Theorem of Calculus:

At $t = 15$ , $f(15) = -\frac{125}{15^3} = -\frac{1}{27}$

At $t = 5$ , $f(5) = -\frac{125}{5^3} = -1$

Then

$P(A) = -\frac{1}{27} + 1 = -\frac{1}{27} + \frac{27}{27} = \frac{26}{27}$

Probability of arriving in less than 15 minutes and less than 10 minutes.

The intersection of these events is less than 10 minutes, so:

$P(B) = \int_{5}^{10} = \frac{375}{t^4}$

We already have the integral, so just apply the limits:

At $t = 10$ , $f(10) = -\frac{125}{10^3} = -\frac{1}{8}$

At $t = 5$ , $f(5) = -\frac{125}{5^3} = -1$

Then

$P(A \cap B) = -\frac{1}{8} + 1 = -\frac{1}{8} + \frac{8}{8} = \frac{7}{8}$

If given the train arrived in less than 15 minutes, what is the probability it arrived in less than 10 minutes?

$P(B|A) = \frac{P(A \cap B)}{P(A)} = \frac{\frac{7}{8}}{\frac{26}{27}} = 0.9087$

Thus 90.87%, approximately 91%, and the correct answer is given by option D.

3 0

3 years ago