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evablogger [386]
3 years ago
5

The speed of a sparrow is x km/h in still air. When the

Mathematics
1 answer:
Semmy [17]3 years ago
4 0

Answer:

x = 5m/s

Step-by-step explanation:

Distance flying out = 12 km  (headwind)

Distance flying back = 12 km (tailwind)

total distance = 12 + 12 =24 km

wind speed = 1km/h

speed going out (with headwind) = (x - 1) km/h

speed coming back (with tailwind) = (x + 1) km/h

Time taken to go out = distance going out / speed going out

= 12 / (x-1)

Time taken to come back = distance coming back / speed coming back

= 12 / (x+1)

total time = time taken to go out + time taken to come back

5 =[ 12/(x-1) ] + [ 12/(x-1)]

expanding this, we will get

5x² - 24x - 5 = 0

solving quadratic equation, we will get

x = -1/5 (impossible because speed cannot be negative)

or

x = 5 (answer)

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The perimeter of a playing field for a certain sport is 300ft. The field is a rectangle, and the length is 48ft longer than the
lara31 [8.8K]

Answer:

Width of the rectangular field =102 feet

Step-by-step explanation:

Perimeter of the field= 300feet

Length of the field= 48 feet

Width=?

Perimeter of a rectangular field= 2(Length+Width)

                                            300= 2(48+Width)\\\\150=48+Width\\\\Width=150-48\\\\Width=102 feet

The Width of the rectangular field is 102 feet

4 0
3 years ago
Read 2 more answers
When obtaining a confidence interval for a population mean in the case of a finite population of size N and a sample size n whic
Elanso [62]

Answer:

95% Confidence interval for the mean

142.8 \leq\mu\leq158.4

Step-by-step explanation:

We have to calculate a 95% confidence interval for the mean of a finite population.

The error is multiplied by the following finite population correction factor:

cf=\sqrt{\frac{N-n}{N-1} }

The standard deviation can be estimated as

\sigma=\frac{s}{\sqrt{n}} \sqrt{\frac{N-n}{N-1} } =\frac{24.4}{\sqrt{32} }* \sqrt{\frac{200-32}{200-1} }=3.963

The 95% confidence interval has a z value of 1.96, so it becomes:

M-z*\sigma_c\leq\mu\leq M+z*\sigma_c\\\\150.6-1.96*3.963\leq\mu\leq 150.6+1.96*3.963\\\\ 142.8 \leq\mu\leq 158.4

5 0
3 years ago
A bus eats 4 people in a row and there are 12 rows how would fit on 2 buses?
BARSIC [14]

Answer:

4 \times 12 \times 2 = 96

96 people in total.

BTW its seats and I think you meant "how many"

6 0
3 years ago
In a store, a sample of 60 pens was selected from a box of 1,200 pens. Of these 60, 4 pens did not work. About how many pens cou
Lapatulllka [165]
Ok so if 1200 total pens and 60 were taken that's a ratio of 1200/60=20

out of 60pens 4 didn't work, again ratio is 4/60=1/15 so about 1/15 of the pens didn't work. 

so we have 1200pens * 1/15broken ratio = 80 pens or we can say 

20*4=80pens won't work from 20 groups of 60 and 4 out of 60 not working is 20*4=80 not working from total batch of 1200.

hope this helps you some! thank you!!!!!!!!!
3 0
3 years ago
How to find area of a rectangle?
anyanavicka [17]

Formula

Area = L*w


Hint : To find the area of a rectangle , multiply the length times the width


I hope that's help !


4 0
3 years ago
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