Answer: 7 people need 16 minutes to paint 4 walls.
Step-by-step explanation:
Since we have given that it takes 63 minutes to paint 9 walls ,
So, we will apply "time and work formula" i.e.

where,
H denotes number of hours or minutes,
D denotes number of days
M denotes number of men
W denotes work done them,
So, we need to calculate number of minutes for 7 people to paint 4 walls,

So, 7 people need 16 minutes to paint 4 walls.
Step-by-step explanation:
To do this, we will substitute the x values to their corresponding equations,
1)

Given 2x + 15 = 19
Calculated 2x + 15 = 19
Given = Calculated, this solution is correct.
2)

Given 3 + x + 2 - x = 16
Calculated 3 + x + 2 - x = 5
Given not equal to calculated, this solution is incorrect.
3)

Given (x+2)/5 = 2
Calculated (x+2)/5 = 2
Given = Calculated, this solution is correct.
4)


Given 2x - 8 = 6
Calculated 2x - 8 = 6
Given = Calculated, this solution is correct.
5)


Given 1/3x + 5 = 14
Calculated 1/3x + 5 = 11
Given not equal to Calculated, this solution is not correct.
Therefore the Correct solutions are 1,3 and 4.
Answer:
Option F
Step-by-step explanation:
F). x + y = 3 -------(1)
x - 3y = -2 --------(2)
Equation (1) minus equation (2)
(x + y) - (x - 3y) = 3 - (-2)
4y = 5
y = 1.25
Hence, y is positive.
G). x + y = 3 --------(1)
x + y = -2 --------(2)
Both the equations represent parallel lines.
There are no solutions of the given equations.
H). x - 3y = -2 -------(1)
x + y = -2 -------(2)
Equation (2) minus equation (1)
(x + y) - (x - 3y) = -2 - (-2)
4y = 0
y = 0
Since, 0 is neither positive nor negative, y will be neither positive nor negative.
J). x + y = 3 -------(1)
x - y = 3 --------(2)
Equation (1) - Equation (2)
(x + y) - (x - y) = 3 - 3
2y = 0
Hence, y is neither negative nor positive.
Therefore, Option F is the answer.
Answer:
Can you attach the figure?
Step-by-step explanation:
No 2.1 is not bigger than 2.20 because when you add a zero to the end of 2.1 it makes it 2.10.