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erastovalidia [21]
3 years ago
13

A car travels the first 50km of its journey at an average speed of 25m/s snd the next 120km at an average speed of 80km/h. The c

ar completes the lat part of its journey at an average speed of 90km/h in 35 minutes. Find the average speed for its entire journey ,giving your answer in km/h.
Mathematics
1 answer:
Alex17521 [72]3 years ago
5 0

Answer:

84,6km/h

Step-by-step explanation:

the whole journey was

in the first part the car travels 50km, in the second part 120km and in the third part we can find it with a simple rule of three

90km--->60 min

X<--------35min= 52.5 km the car made in the last part

50km+120km+52,5km=222.5km was all the journey

and he made it in:

  • the last part in 35min,
  • in the second part we know that the car was going at 80km/h and that he made 120km so:

80km--->60 min

120km--->90 min

  • in the first part we know that the car was going at 25m/s and he made 50km. 25m/s*1km/1000m*3600s/1h= we obtain the speed in km/h=90km/h

90km---->60min

50km---->x=33,333 min

The whole journey last 33,333min+90min+35min=158.333min

if we express that in hour = 158.333min*1hr/60min=2.63

the car made 222.5km in 2.63 hour

so the average speed was

222.5---->2.63hr

X--------1hr=84,6

the average speed was 84,6km/h

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Clark Heter is an industrial engineer at Lyons Products. He would like to determine whether there are more units produced on the
Alborosie

Answer:

Step-by-step explanation:

Let the subscripts d and n represent day and night respectively

The null hypothesis is

H0 : μd ≥ μn

The alternative hypothesis is

H1 : μd < μn

it is a one-tailed and also a right left test because of the greater than symbol in the alternative hypothesis.

The decision rule is to reject H0: μd ≥ μn If 0.10 > p value

Since the population standard deviations are known, we would use the formula to determine the test statistic(z score)

z = (xd - xn)/√σd²/nd + σn²/nn

Where

xd and xn represents sample means for day and night respectively.

σd and σn represents population standard deviations for day and night respectively.

nd and nn represents number of samples

From the information given,

xd = 334

xn = 341

σd = 23

σ2 = 28

nd = 60

nn = 68

z = (334 - 341)/√23²/60 + 28²/68

= - 7/√20.34607843138

z = - 1.55

From the normal distribution table, the probability value corresponding to the z score is 0.061

Since the level of significance, 0.1 > 0.061, we would reject H0

Therefore, there is enough evidence to conclude that there are more units produced on the night shift than on the day shift.

8 0
3 years ago
A buoy moves up and down with the waves in simple harmonic motion. This buoy moves a total of 12 feet from its minimum position
Lana71 [14]
That was rude of him
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3 years ago
If the measure of angle 4 is (11 x) degrees and angle 3 is (4 x) degrees, what is the measure of angle 3 in degrees?
GarryVolchara [31]

Answer:

B

Step-by-step explanation:

Angle 4 × Angle 3 = 90

Complementary angles

11x + 4x = 90

15x = 90

x = 6

Angle 3 = 4x = 4(6) = 24°

5 0
3 years ago
Read 2 more answers
Round 71.491 to the place of the underlined digit which is the 4
TiliK225 [7]
When rounding the 4 you look to the right of the number, which is the 4, and if the number is higher than 5 you would change the 4 to 5. 
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5 0
3 years ago
The GCD(a, b) = 9, the LCM(a, b)=378. Find the least possible value of a+b.
denis-greek [22]
\mathrm{gcd}(a,b)=9\implies9\mid a\text{ and }9\mid b\implies9\mid a+b

which means there is some integer k for which a+b=9k.


Because 9\mid a and 9\mid b, there are integers n_1,n_2 such that a=9n_1 and b=9n_2, and


\mathrm{lcm}(a,b)=\mathrm{lcm}(9n_1,9n_2)=9\mathrm{lcm}(n_1,n_2)=378\implies\mathrm{lcm}(n_1,n_2)=42

We have 42=2\cdot3\cdot7, which means there are four possible choices of n_1,n_2:

1, 42
2, 21
3, 14
6, 7

which is to say there are also four corresponding choices for a,b:

9, 378
18, 189
27, 126
54, 63

whose sums are:

387
207
153
117

So the least possible value of a+b is 117.
6 0
3 years ago
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