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]
3 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]3 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]3 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
Whats the volume?<br><br> B= 37.6 cm²; h= 20 cm
Georgia [21]

Answer:

752 cm^3

Step-by-step explanation:

Find the volume with: base x length x height

37.6 x 20 = 752

8 0
3 years ago
How do i do this pls help me
Delvig [45]

Answer:

y =  \frac{1}{7} x + 7

Step-by-step explanation:

x-7y = -49

i) move x to the right-hand side and change its sign

-7y = -49-x

ii) change the signs on both sides of the equation

7y = 49+x

iii) divide both sides of the equation by 7

\frac{7y}{7}  = \frac{49}{7}  +  \frac{x}{7}

y = 7 +  \frac{1}{7}  x

iv) use the commutative property to reorder the terms

* commutative property: a+b = b+a

y =  \frac{1}{7} x + 7

3 0
3 years ago
5. help me i’ll give brainliest if you’re right
-Dominant- [34]

Answer:

can i have my brainliest i helped u on the other questions pls dude

Step-by-step explanation:

7 0
3 years ago
If the null space of a 5 × 8 matrix A is 4-dimensional, what is the dimension of the column space of A? dim Col A-(Simplify your
Eva8 [605]

Answer:  Dim Col A = 4.

Step-by-step explanation:

Since we have given that

Matrix A has 5 rows and 8 columns.

And Nul A = 4

It implies that the rank of A would be

Number of columns - Nul A =  8 - 4 =4

So, rank A = 4

so, it has dim Col A = 4 also.

But the four vector basis lie in R⁵.

Hence, Dim Col A = 4.

5 0
3 years ago
A bag contains 6 red marbles, 5 blue marbles and 8 green marbles. If three marbles are drawn out of the bag, what is the probabi
SVETLANKA909090 [29]

Answer: 5.8%

Step-by-step explanation:

In this situation there is no replacement so we have to mulitply the probablilty of the first,second, and third marble being green. First marble has a 8/19 probablilty of being selected because 19 total marbles in the bag and 8 green marbles. the next marble will have a 7/18 probabililty because now only 18 marble are in the bag and we are assuming we selected a green marble on our first draw. Same thing with the last green marble it would be 6/17 because there would be 17 marbles in the bag and 6 green ones left assuming we got the first 2

so 8/19*7/18*6/17=

56/969=

0.05779

5.77%

5.8%

3 0
3 years ago
Other questions:
  • Change 290 degrees to radian measure in terms of pi.
    6·1 answer
  • How do you simplify (3x+1/2)+(7x-41/2)
    7·1 answer
  • Standard of living is the level at which
    7·1 answer
  • Which equation represents the line that passes through the points (-6,7) and (-3,6)?
    15·2 answers
  • Which of the following points lies on the graph of this equation? y = 2x – 2 Select one: a. (-1, -1) b. (1, 0) c. (1, 4) d. (-1,
    5·1 answer
  • Please help!! look at the picture as well!!
    11·1 answer
  • The volume (V) of a cube is 216 cubic Inches. What is the surface area (S) of the cube?
    9·1 answer
  • Solve for x in the equation below.
    8·1 answer
  • What is the slope of the line
    12·1 answer
  • Can you anyone please help me?<br>​
    15·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!