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
4vir4ik [10]
3 years ago
13

If Alex and Brandon work together they will clean the school in 15 hours. Working alone, Brandon can finish the same job in 20 h

ours. How long will it take Alex to do the job by himself? PLEASE HELP ME PRETTY PLEASE
Mathematics
1 answer:
sesenic [268]3 years ago
8 0

Answer:

It takes 60 hours for Alex to complete the job alone.

Step-by-step explanation:

Given:

Number of hours Brandon alone can finish job =20 hours

Let the number of hours required by Alex alone to complete the job be 'x' hrs.

We need to find the number of hours required by Alex alone to complete the job.

Solution:

Now we can say that;

Rate at which Alex can complete the job alone = \frac1x job/hour

Rate at which Brandon can complete the job alone = \frac{1}{20} job /hour

Also Given:

Number of hours required for both to complete the job = 15

So rate of both complete the job  = \frac{1}{15} job/hour

Now we can say that;

rate of both complete the job is equal to sum of Rate at which Alex can complete the job alone and Rate at which Brandon can complete the job alone.

framing in equation form we get;

\frac1x+\frac{1}{20}=\frac{1}{15}

Now taking LCM for making the denominators same we get;

\frac{20}{20x}+\frac{x}{20x}=\frac{1}{15}

Now denominators are common so we will solve the numerators.

\frac{20+x}{20x}=\frac{1}{15}

Now Using cross multiplication we get;

15(20+x)=20x

Applying Distributive property we get;

15\times20+15\times x =20x\\\\300+15x=20x

Combining like terms we get;

300=20x-15x\\\\300=5x

Now Dividing both side by 5 we get;

\frac{300}{5}=\frac{5x}{5}\\\\x=60\ hrs

Hence It takes 60 hours for Alex to complete the job alone.

You might be interested in
Write the standard equation for the circle with center (–2, 5) that passes through (1, 9).
maksim [4K]
All given options are incorrect .. As no one is the equation of a circle
6 0
3 years ago
Read 2 more answers
Lesson 10: Congruent Triangles ._.
spayn [35]
#1 is A
#2 IS c
#3 is B
3 0
3 years ago
Read 2 more answers
What is the value of x?
stiks02 [169]

Answer:

Step-by-step explanation:

Use Pythagoras Theorem

x² + 16² = 34²

x² + 256 =  1156

x² = 1156 - 256

x² = 900

x= √3*3*10*10

x= 3*10

x = 30

4 0
3 years ago
Read 2 more answers
How can you write the expression with rationalized denominator? sqrt3 - sqrt6 / sqrt 3 + sqrt 6
harina [27]
Answer:  2√2 - 3

Explanation:


The expession written properly is:

\frac{ \sqrt{3}- \sqrt{6}  }{ \sqrt{3}+ \sqrt{6} }

To rationalize that kind of expressions, this is to eliminate the radicals on the denominator you use conjugate rationalization.

That is, you have to multiply both numerator and denominator times the conjugate of the denominator.

The conjugate of √3+√6 is √3 - √6, so let's do it:

\frac{ \sqrt{3} - \sqrt{6} }{ \sqrt{3} + \sqrt{6} } . \frac{ \sqrt{3}- \sqrt{6}  }{ \sqrt{3}- \sqrt{6} }

To help you with the solution of that expression, I will show each part.

1) Numerator: (√3 - √6) . (√3 - √6) = (√3 - √6)^2 = (√3)^2 - 2√3√6 + (√6)^2 =

= 3 - 2√18 + 6 = 9 - 6√2.

2) Denominator: (√3 + √6).(√3 - √6) = (√3)^2 - (√6)^2 = 3 - 6 = - 3

3) Then the resulting expression is:

 9 - 6√2
-----------
 -3

Which can be further simplified, dividing by - 3

    -3 + 2√2

Answer: 2√2 - 3

7 0
3 years ago
Read 2 more answers
Find the measure of c. A. 40 B. 70 C. 90 D. 50
Juliette [100K]

Answer:

D. 50

Step-by-step explanation:

a = 90° (angle subtended in semicircle)

a + c + 40° = 180° (by angle sum postulate of a triangle)

90° + c + 40° = 180°

c + 130° = 180°

c = 180° - 130°

c = 50°

4 0
3 years ago
Other questions:
  • A gallon of gas costs g dollars. paul puts 12.5 gallons of gasoline in his car and 0.75 gallon of gasoline in a portable tank. w
    13·1 answer
  • HELP FAST NOW PLEASE IM HAVING TROUBLE!!
    11·2 answers
  • Y + 4/9 = 2/3 Solve the equation..
    9·1 answer
  • T(8,2) is reflected across the x-axis.
    8·1 answer
  • What is the surface area of a rectangular prism that has a height of 5 cm, a width of 10 cm, and a depth of 4 cm?
    13·2 answers
  • Bob Woodward and Carl Bernstein were Washington Post journalists whose reports during the Watergate affair led to the resignatio
    14·2 answers
  • A mathematics textbook has 6 pages of instruction for every 2 pages of practice problems. How many pages of instruction does it
    7·1 answer
  • The Thomas' backyard pool is
    7·1 answer
  • Over a 30-day period, the mean temperature in Morristown was 56°F with a standard deviation of 8.4°F and the mean temperature in
    15·1 answer
  • How can you rewrite the number 1 as 10 to a power?
    12·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!