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
castortr0y [4]
2 years ago
12

If a varies directly as b, and a = 28 when b = 7, find b when a = 5.

Mathematics
2 answers:
Rufina [12.5K]2 years ago
6 0
If a varies directly as b:
a = k b
28 = 7 k
k = 28 : 7 = 4
When a = 5:
5 = 4 b
b = 5 : 4
b = 1.25
Jlenok [28]2 years ago
4 0

Answer:

Value of b = \frac{5}{4} =1.25.

Step-by-step explanation:

Direct Variation states that a relationship  between two variables in which one is a constant multiple of the other.

*if one variable changes the other changes in proportion to the first.

*If a is directly proportional to b i.e,  

a \propto b then it is of the form

a = kb     ;where k is constant variation.  

Given: a varies directly as b;

then, by definition of direct variation;

we have;

a = kb             .....[1]

Substitute the value of a =28 and b =7 to solve for k;

28 = k(7)

Divide both sides by 7 we have;

\frac{28}{7}=\frac{7k}{7}

Simplify:

k =4

now, find b using same method when a =5;

then;

after substituting the value of a = 5 and k=4 in [1] ;

5=(4)b

Divide by 4 to both sides we get;

b =\frac{5}{4}

Therefore, the value of b = \frac{5}{4} =1.25



You might be interested in
The greater of two consecutive integers is 20 more than twice the smaller. find the integers.
Kipish [7]

Let x represent the smaller. Then x+1 is the greater of the two.

... x+1 = 2x +20

... 0 = x + 19 . . . . . subtract x+1

... x = -19

Your two integers are -19 and -18.

7 0
3 years ago
Simplify the following:<br>3.2.1 (5x)=(2xy)<br>15xy​
Monica [59]

Answer:

x=\frac{1}{6y^{2} }  ,x=0; y\neq 0

Step-by-step explanation:

7 0
2 years ago
How do I solve this problem?
Andrews [41]

so the line is dog so we know the full line is 60 units long. The 2 parts (do and og) add up to the full length so we can make the equation:

(4x-3)+(2x+21)=60

6x+18=60

6x=42

x=7

if you need to fine do or og, just plug in x to its equation

6 0
3 years ago
Please help need answers
bogdanovich [222]

see explanation below

(1) \frac{1}{5} × \frac{2}{2} = \frac{2}{10} = 0.2

(2) \frac{6}{25} × \frac{4}{4} = \frac{24}{100} = 0.24

(3) 2 \frac{3}{4} = 2 +\frac{75}{100} = 2.75

(4) 3 \frac{9}{10} = 3 + 0.9 = 3.9

(5) 1.25 = 1 \frac{1}{4} = \frac{5}{4}

(6) 3.29 = 3 \frac{29}{100} = \frac{329}{100}

(7) 0.65 = \frac{65}{100} = \frac{13}{20} in simplest form

(8) 5.6 = 5 \frac{6}{10} = 5 \frac{3}{5} = \frac{28}{5}

(9) he is incorrect

\frac{3}{5} × \frac{20}{20} = \frac{60}{100} = 0.6 ≠ 3.5


7 0
3 years ago
Tyler baked 702 cookies he sold them in boxes of 18 after selling all of the boxes of cookies for the same amount of each he ear
jenyasd209 [6]

Keywords:

<em>Cookies, boxes, sale, profit, unit cost </em>

For this case we have to bake an amount of 702 cookies, which were distributed in boxes of 18 for sale. Selling each box at the same price earned a profit of 136.50 dollars, you want to know the unit cost of each box of cookies.

Let "x"be the number of boxes of cookies:

So, to know the number of boxes we divide 702 cookies among 18:

x = \frac {702} {18}\\x = 39

So, we have Tyler sold 39 boxes of cookies

Now, let "y" be the cost of each box of cookies, to know the unit cost or sale price of the cookie boxes, we divided 136.50 dollars among 39 boxes of cookies, then:

y = \frac {136.50} {39}\\y = 3.5

Thus, the cost of each box was 3.5 dollars.

Answer:

The cost of a box is 3.5 dollars

5 0
3 years ago
Read 2 more answers
Other questions:
  • How many centimeters are in x meters???
    5·2 answers
  • Help please!!! Thxxx
    7·1 answer
  • Bass Pro has a sale on boats! Just what you have always wanted and it is $3000 cheaper than it usually
    9·1 answer
  • Marcy’s breakfast table has a square table top with an area of 36 square feet. What is the diagonal length of the table top?
    13·2 answers
  • Help me figure out how they got 63sq ft.
    12·1 answer
  • Susie has planned a trip to a city 60 miles away. She wishes to have an average speed of 60 miles/hour for the trip. Due to a tr
    5·1 answer
  • What is the answer to the problem??
    14·1 answer
  • Please write a persuasive essay on why parents are more important than peers.​
    7·2 answers
  • Mateo has already swum Four-fifths of the 2,000 meters he is swimming today. If he continues swimming at a pace of Three-fourths
    5·1 answer
  • Your bank account has -$30, and you deposit $7 daily. How much money is your account after 5 days? Show you work with the Unit!
    13·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!