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
erastovalidia [21]
4 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]4 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

You might be interested in
Mr.francos records show that 25% of his students bring their own lunches to school. which decimal represents the percent of stud
masya89 [10]

Answer:

c=100%-25%=75%

=75/100=0.75

6 0
3 years ago
Suppose that news spreads through a city of fixed size of 700000 people at a time rate proportional to the number of people who
Gnoma [55]

Answer:

y'(t) = k(700,000-y(t))  k>0 is the constant of proportionality

y(0) =0

Step-by-step explanation:

(a.) Formulate a differential equation and initial condition for y(t) = the number of people who have heard the news t days after it has happened.

If we suppose that news spreads through a city of fixed size of 700,000 people at a time rate proportional to the number of people who have not heard the news that means  

<em>dy/dt = k(700,000-y(t)) </em>where k is some constant of proportionality.

Since no one has heard the news at first, we have

<em>y(0) = 0 (initial condition) </em>

We can then state the initial value problem as

y'(t) = k(700,000-y(t))

y(0) =0

8 0
3 years ago
$4500 at 5.5% for 4/1/2 Year’s
AnnyKZ [126]
The answer might be 299.26. Sorry if it’s not
3 0
3 years ago
Read 2 more answers
26. (02.08)
Mama L [17]

Answer:

X^2 -5x -36

Step-by-step explanation:

formula of an area of a rectangle: ab

a-length

b-width

(x+4)*(x-9) = x^2 -5x -36

7 0
3 years ago
Michelle took one of her friends out to lunch. The lunches cost $74 and
Reika [66]

Answer:

$91. 91

Step-by-step explanation:

i used a tip and tax calculator :))) hope this helps

8 0
3 years ago
Other questions:
  • Please help asap, no rocky!
    13·2 answers
  • Which equations are equivalent to 3/4 + m = -7/4? Select three options.
    13·1 answer
  • What’s 54/65 as a decimal rounded to the nearest thousandth
    8·1 answer
  • The temperature at 6:006:00 a.m. was ‐3.5°C‐3.5°C. From 6:006:00 to 7:007:00, the temperature increased 2.5°C2.5°C. From 7:007:0
    12·2 answers
  • What does x and y equal
    13·1 answer
  • Compare the values and order them from least to greatest ???
    6·1 answer
  • Find each factor polynomal 3x^3+9x^2
    8·2 answers
  • Pleaseee helppp mee!!
    7·1 answer
  • The value of a particular stock is increasing at a rate of 7% every month.
    13·1 answer
  • Write an equation with a variable AND solve it. Mario read 72 pages of his book in class and 13 pages per night, n, until he rea
    13·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!