Answer:
x = - 4
Step-by-step explanation:
Given
x + 4 = 
x
Multiply through by 3 to clear the fractions
5x + 12 = 2x ( subtract 2x from both sides )
3x + 12 = 0 ( subtract 12 from both sides )
3x = - 12 ( divide both sides by 3 )
x = - 4
Since the average height is 60 inches and its deviation is 2 inches, one deviation to the right (or higher) is 62 inches (60 + 2). Two deviations is 64 inches, three deviations is 66 inches, and four deviations is 68 inches.
Since the average weight is 100 pounds and its deviation is 5 inches, we repeat the process from finding heights to get to 115 pounds. That takes three deviations.
The MORE deviations away, the more unusual it is. So the height (4 deviations) is more unusual than the weight (3 deviations).
Answer:
x: work a woman can do in 1 day
y: work a girl can do in 1 day
Then
2x + 7y =1/4
4x + 4y =1/3
4x + 14y =2/4 (1)
4x + 4y =1/3 (2)
=> Let (1) - (2), 10y =2/4-1/3 <=>10y = 1/6 <=> y = 1/(6x10) = 1/60 (work)
=> From (2),4x = 1/3 - 4x1/60 => 4x = 16/60 => x = 4/60 (work)
=> 1 day, a woman and a girl can do: 1/60+4/60 = 5/60 =1/12 (work)
Then, the day required for a woman and a girl to complete work: 12 days
