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RSB [31]
3 years ago
11

How to solve these? I would like explanation please

Mathematics
1 answer:
GuDViN [60]3 years ago
5 0

Step-by-step explanation:

9.

it is a rectangle. 18m × 4m = 72 m²

the paving costs $35 per m², and we have 72 m², so it does not take a genius to figure out what to do next ...

right : we multiply 35 by 72

35×72 = $2520

10.

how much volume is a liter ?

a liter fits into a cube of 10cm side length.

and 1 meter = 100 cm = 10×10cm.

so, 1 m³ = 10×10×10 = 1000 such cubes of 10cm side length = 1000 liters.

the pool is 5 m × 15 m × 1.5 m = 112.5 m³ = 112500 liters

we need 2 kg salt for every 10000 liters water, so we have how many units of 10000 liters in the pool ?

112500 / 10000 = 11.25

so, we need

11.25 × 2 = 22.5 kg salt

11.

12 seconds = 1/5 of a minute.

so, batman runs at 3 km / min (= 60×3 km/hour = 180 km/h - not possible in real life for any human being, but let's play ...) for 12 seconds = 1/5th of a minute, and so he runs 3km/5 = 600 meters in that time.

that means he has 2km - 600m = 1400m left to run in the 2 km race.

it takes him 1400/3000th of a minute (3000 m would take him the full minute)

1400 m × minute / 3000 m = 14/30 = 7/15 minutes

1/15th minute = 60 seconds / 15 = 4 seconds.

so, 7/15th of a minute = 7×4 seconds = 28 seconds.

the bionic woman runs the full 2000 m with 5 km / minute.

it takes her 2000/5000th of a minute

2000 m × minute / 5000 = 2/5th of a minute.

1/5th of a minute is 60 seconds / 5 = 12 seconds.

so, 2/5th of a minute is 12×2 = 24 seconds.

therefore, the bionic woman wins by 4 seconds (24 seconds vs. 28 seconds).

12.

there is enough food for 150 students for 5 days = 150×5 =750 "food units".

therefore, if there were only 100 students, the food would last 750/100 = 7.5 days.

and if the food runs out after 4 days it means there are

750/4 = 187.5 students (how much sense that makes to have half a student ...).

13.

x = the workload to be done

Michelle's work speed is x/6 days

Danielle's work speed is x/4 days

on each day working together they achieve

1× x/6 + 1× x/4 of the total work load.

that is

2x/12 + 3x/12 = 5x/12

so, they need 5x/12 × a days to finish the whole x.

5x/12 × a = x

5/12 × a = 1

5a = 12

a = 12/5 = 2.4 days to finish the whole work when working together.

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GIVEN THAT TITAN HAS A RADIUS OF 2575 KM WHICH IS COVERED BY 600 KM ATMOSPHERE. WHAT
Ber [7]

Answer:

  87.4%

Step-by-step explanation:

The radius to the top of the atmosphere as a fraction of the moon's radius is ...

  (2575 +600)/2575 ≈ 1.23301

The ratio of the moon's volume with atmosphere to the moon's volume without is the cube of this, or 1.87456

Then the ratio of the atmosphere's volume to the moon's volume is ...

  (1.87456 -1)/1 = 0.87456

Atmospheric haze is about 87.4% of the moon's volume.

_____

We have assumed that the desired ratio is to the solid moon's volume, not the volume of moon and atmosphere together. The latter ratio would be 0.875 to 1.875 or about 46.7%.

3 0
3 years ago
Find the perimeter of the figure
Anna11 [10]
The perimeter is 64 yards.
6 0
3 years ago
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6:15:21 in its simplest form
Readme [11.4K]

6:15:21

6:15:21= 2:5:7

<em>(when divided by 3)</em>

7 0
3 years ago
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Evaluate the expression x^4+9x^2 when x=-3
aalyn [17]

Answer:

162

Step-by-step explanation:

Step 1: Define

x⁴ + 9x²

x = -3

Step 2: Substitute and Evaluate

(-3)⁴ + 9(-3)²

81 + 9(9)

81 + 81

162

6 0
3 years ago
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P(X&lt; ) 1-P(X&gt; ) A softball pitcher has a 0.626 probability of throwing a strike for each curve ball pitch. If the softball
Mashutka [201]

Answer:

19.49% probability that no more than 16 of them are strikes

Step-by-step explanation:

Binomial probability distribution

Probability of exactly x sucesses on n repeated trials, with p probability.

Can be approximated to a normal distribution, using the expected value and the standard deviation.

The expected value of the binomial distribution is:

E(X) = np

The standard deviation of the binomial distribution is:

\sqrt{V(X)} = \sqrt{np(1-p)}

Normal probability distribution

Problems of normally distributed samples can be 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.

When we are approximating a binomial distribution to a normal one, we have that \mu = E(X), \sigma = \sqrt{V(X)}.

In this problem, we have that:

n = 30, p = 0.626

So

\mu = E(X) = np = 30*0.626 = 18.78

\sigma = \sqrt{V(X)} = \sqrt{np(1-p)} = \sqrt{30*0.626*0.374} = 2.65

What is the probability that no more than 16 of them are strikes?

Using continuity correction, this is P(X \leq 16 + 0.5) = P(X \leq 16.5), which is the pvalue of Z when X = 16.5. So

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

Z = \frac{16.5 - 18.78}{2.65}

Z = -0.86

Z = -0.86 has a pvalue of 0.1949

19.49% probability that no more than 16 of them are strikes

7 0
3 years ago
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