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
nignag [31]
3 years ago
7

Mr. Blue drove from Allston to Brockton, a distance of 105 miles. On his way back, he increased his speed by 10 mph. If the jour

ney back took him 15 minutes less time, what was his original speed?
Mathematics
2 answers:
MrMuchimi3 years ago
8 0

Answer:

60 mph

Step-by-step explanation:

andrew-mc [135]3 years ago
5 0

Answer:

His original speed was 60 mph.

Step-by-step explanation:

The average speed formula is shown below:

speed = distance / time

For the first leg of the trip Mr. Blue drove at a speed of "x" mph, for a distance of 105 miles, therefore the time that took to complete the trip is:

time 1 = distance / speed

time 1 = 105 / x h

On the second leg of the trip Mr. Blue drove faster at a speed of "x + 10" mph, so the time it took him to complete the trip was 15 minutes less, therfore:

time 2 = time1 - (15/60) = (105/x) - 0.25 = (105 - 0.25*x)/x h

Applyint the time and speed from the second leg to the average speed formula we have:

x + 10 = {105/[(105 - 0.25*x)/x]}

x + 10 = 105*x/(105 - 0.25*x)

(x + 10)*(105 - 0.25*x) = 105*x

105*x + 1050 -0.25*x² - 2.5*x = 105*x

-0.25*x² -2.5*x + 1050 = 0 /(-0.25)

x² + 10*x - 4200 = 0

x1 = [-(10) + sqrt((10)² - 4*(1)*(-4200))]/2 = 60

x2 = [-(10) - sqrt((10)² - 4*(1)*(-4200))]/2 = -70

Since his speed couldn't be negative the only possible value was 60 mph.

You might be interested in
A population grows with an annual growth rate of 16.5 % per year. (a) what is the monthly growth rate
Shtirlitz [24]
The monthly growth rate would be 16.5% divided by 12 which is 1.3%
8 0
3 years ago
A can of soda in 1972 costs $0.15, by 2012 it cost $1.35 find the rate at which the cost of a can of soda increases over this ti
fenix001 [56]

Answer:

800%

Step-by-step explanation:

<h2><u>Percentage increase</u></h2><h3><u>formula:</u></h3>

change/ original * 100

change is 1.35 - 0.15 = 1.2

original is the amount in the beginning which is 0.15

= 1.2/0.15 * 100

=800 %

<em><u>the percentage increase is by 800%</u></em>

8 0
2 years ago
Ryan is selling a new computer system that he designed. He spent $200
Neporo4naja [7]

Answer:

Ryan should mark the price as $300.

Step-by-step explanation:

If he wants to markup his price by 50%, you first take 50% of $200 which is $100, then you add it to the original price 200+100= $300

4 0
2 years ago
Whats 4 2/5 x 1 1/2 pls help​
Veronika [31]
The answer is that (It’s 6.6)
8 0
2 years ago
Read 2 more answers
The system of equations has no solution:<br> y=2/3x-5<br> 4x - 6y = 30<br> true or false?
Serjik [45]

1. y = 2/3x - 5

2. 4x - 6y = 30

Divide 2. by 2

3. 2x - 3y = 15

Substitute 1. into 3.

4. 2x - 3(2/3x - 5) = 15

5. 2x - 2x + 15 = 15

6. 15 = 15

False. There are an infinite number of solutions.

3 0
2 years ago
Other questions:
  • PLEASE HELP&lt; YOU WILL RECEIVE BRAINLIEST AND 50 POINTS!PLEASE DO NOT ANSWER THIS IF YOU DO NOT KNOW IT!
    13·2 answers
  • Why do teachers say math is so important
    5·2 answers
  • What is 7% of $7.40​
    15·1 answer
  • PLEASE HELP?!?!?!
    5·1 answer
  • PLS OMG!!! i need to pass bro omg pls just please help.
    13·1 answer
  • A jewelry box containes 3 rings, 7 necklaces, 4 earrings, 5 braceletes and 1 tiara. If 1 piece of jewlery is selected at radom,
    15·2 answers
  • A college surveys local businesses about the importance of students as customers. The college chooses 150 businesses at
    6·1 answer
  • Mateo made 36 cookies with nuts. He also made 12 fewer cookies without nuts.
    9·2 answers
  • I need help plz answer
    9·2 answers
  • Write expression that is equivalent to 1/4 a -3
    14·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!