1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Alinara [238K]
3 years ago
8

How to do answer 16, 19 and 21? Please show me the solutions. ​

Mathematics
2 answers:
Pepsi [2]3 years ago
8 0

Answer:

The speed in still air =  200 mph.

Step-by-step explanation:

21.

If the speed of the plane in still air is  x mph then with the wind its speed is x+20 mph and against the wind it is x - 20 mph. Also let t hours be the time taken for the journey with the wind.

So we have the 2 equations:

x + 20 = 396 / t

x - 20 =  396 / (4 - t)

Subtracting to eliminate  x

40 =   396 / t - 396 / (4 - t)

40t(4 - t) = 396(4 - t) - 396t

160t - 40t^2 = 1584 - 396t - 396t

-40t^2 + 952t  - 1584 = 0

Dividing through by 8:

-5t^2 + 119t - 198 = 0

Using the quadratic formula we get t = 22,  1.8 hours . We ignore the 22 because  the total time is 4 hours.

So the speed x =  is found by plugging in t  1.8:

x + 20 = 396/1.8

x =  200 mph.

Zolol [24]3 years ago
6 0

Answer:

16) the boy is 11 years old

Step-by-step explanation:

16) Let the boy’s present age be b.

b+5 = 4(b-9)^2, or

b+5 = 4[b^2–18b+81] = 4b^2–72b+324, or

4b^2–73b+319 = 0, or

(4b-29)(x-11) = 0, or

b = 11 or 7.25 years. The second value is inadmissible.

So the boy is 11 years old, now.

You might be interested in
whats the answer to the diameter of a circle with a circumference of 50mm rounded to the nearest tenth?
barxatty [35]
The diameter of the the circle would be 15.92 mm so if you rounded that up it would 16.
8 0
4 years ago
Oatmeal is made by mixing 15 cups of hot water to 6 cups of oats.
skad [1K]

9514 1404 393

Answer:

  • 2/5 cups oats per cup water
  • 2.5 cups water per cup oats

Step-by-step explanation:

The denominator of the fraction is the unit you want 1 of.

  (6 cups oats)/(15 cups water) = (6/15) cups oats/(1 cup water)

  = (2/5 cups oats)/(1 cup water)

1 cup of water would need 2/5 cups of oats.

__

Obviously, the other ratio is the reciprocal of this.

  (1 cup water)/(2/5 cups oats) = (5/2 cups water)/(1 cup oats)

1 cup of oats would need 2.5 cups of water

7 0
3 years ago
What is the measure of <x​
BabaBlast [244]

Answer:

Y=76⁰

X=104⁰

Z=104⁰

Step-by-step explanation:

Y is equal to 76 bcz directly opposite angles are equal

x=180-76 which is 104⁰ bcz angles on a straight line add up to 180⁰

7 0
3 years ago
(2,1) (0,-7) write in slope intercept form please hurry!
KATRIN_1 [288]
Find slope: (y2-y1)/(x2-x1)
(-7-1)/(0-2) = -8/-2 = 4
Slope int form: y = mx + b
Y = 4x + b
Plug in a point
1 = 4(2) + b, b = -7
Equation: y = 4x - 7
4 0
3 years ago
A roof on a castle tower is shaped like a cone with a diameter of 12 feet and has a slant height of 13 feet one bundle of Shingl
marissa [1.9K]

Answer:

  8

Step-by-step explanation:

The lateral area of a cone is ...

  LA = (π/2)ds

where d is the diameter, and s is the slant height.

The area of this tower roof is about ...

  LA = (π/2)(12 ft)(13 ft) = 78π ft² ≈ 245 ft²

About 245/32 = 7.7 bundles of shingles will be required for coverage.

You should buy 8 bundles of shingles to cover the roof.

8 0
3 years ago
Other questions:
  • Determine the absolute value. Type the numerical answer only. -l12l​
    6·1 answer
  • If 15+3x=3(2−2x), then x= [blank]
    10·1 answer
  • Mel needs to park his car for 8 hours.  Spike’s charges $5.00 per hour for the first hours and $3.00 for each 30 minutes after.
    9·1 answer
  • Explain the triangle angle sum property
    13·2 answers
  • (PLEASE HELP)You draw a card from a deck. Find the probability that you will draw a red card OR a club. (Answer as a percent inc
    6·1 answer
  • Help me please! Asap (ScreenShot)
    13·1 answer
  • 1
    10·1 answer
  • What is the number based on the list of factors? 1,3,7, __<br> Please help
    9·1 answer
  • Help plz Lucia and Randy have signed a contract to purchase a home. The closing date is March 27, a
    14·2 answers
  • PLEASE HELP ME OUT WITH METRIC CONVERSIONS!!!!!!
    5·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!