We know the slope of this line is 1/3x, which means the slope of the line that is perpendicular to it is -3x
A slope that is perpendicular to another is the negative reciprocal of the other.
The equation of a line that is perpendicular to the line y = 1/3x - 5 is y = -3x - 5
Answer: A intersect B is 1 and 3
Let's say Mary's brother's age is x and Mary's age is y
(1) x = 3y - 5
(2) x + y = 39
Now if we substitute equation (1) into equation (2) we get:
3y - 5 + y = 39
4y = 44
y = 11
Therefor Mary is 11 years old
The problem states that the current value is $350 and that is the original price plus 40%, that is $350 is the 140%, the question is how much is the 100%, or the original price, lets use a rule of three, simple, direct proportion:
140% --------> $350
100% --------> x
x = (100)(350)/140
x = 250
that is the original price, $250
