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Genrish500 [490]
3 years ago
12

we need to make a number code with 4 digits. how many codes have at least two equal digits? and how many codes have exactly 3 eq

ual digits?
Mathematics
1 answer:
Blizzard [7]3 years ago
6 0

Answer:

First do the case in which none of the digits is 0.

There are 9 ways to choose the digit that repeats 3 times and 8 ways to pick the other, after this there are 4 ways to order the digits. So 9×8×4.

Now we look at the cases in which the digit 0 repeats 3 times. Clearly the 9 numbers are 1000,2000,3000,…,9000.

Lastly we look at the cases in which 0 appears once. There are 9 ways to pick the other digit and 3 ways to order.

So the final answer is 9×8×4+9+9×3.

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An imaginary number has which of the following as a definition?
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Her is the definition of an imaginary number An imaginary number is a complex number that can be written as a real number multiplied by the imaginary unit i, which is defined by its property i2 = −1. The square of an imaginary number bi is −b2. For example, 5i is an imaginary number, and its square is −25. Zero is considered to be both real and imaginary.
(Got that from google)
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4 years ago
A gasoline tank for a certain car is designed to hold 15 gallons of gas. Suppose that the actual capacity of a randomly selected
marta [7]

Answer:

Tanks of 15.3081 gallons and larger are considered too large.

Step-by-step explanation:

Problems of normally distributed samples are solved using the z-score formula.

In a set with mean \mu and standard deviation \sigma, the zscore of a measure X is given by:

Z = \frac{X - \mu}{\sigma}

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.

In this problem, we have that:

\mu = 15, \sigma = 0.15

How large does a tank have to be to be considered too large

largest 2%, so at least the 98th percentile.

The 98th percentile is X when Z = 0.98. So it is X when Z = 2.054.

Z = \frac{X - \mu}{\sigma}

2.054 = \frac{X - 15}{0.15}

X - 15 = 2.054*0.15

X = 15.3081

Tanks of 15.3081 gallons and larger are considered too large.

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Answer:

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Step-by-step explanation:

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Answer:

y=4x−14

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kap26 [50]

Answer:

true

Step-by-step explanation:

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