When ever you have percentages, it should be helpful to bear in mind you can express them as multipliers. In this case, it will be helpful.
So, if we let:
a = test score
b = target score
then, using the information given:
a = 1.1b + 1
a = 1.15b - 3
and we get simultaneous equations.
'1.1' and '1.15' are the multipliers that I got using the percentages. Multiplying a value by 1.1 is the equivalent of increasing the value by 10%. If you multiplied it by 0.1 (which is the same as dividing by 10), you would get just 10% of the value.
Back to the simultaneous equations, we can just solve them now:
There are a number of ways to do this but I will use my preferred method:
Rearrange to express in terms of b:
a = 1.1b + 1
then b = (a - 1)/1.1
a = 1.15b - 3
then b = (a + 3)/1.15
Since they are both equal to b, they are of the same value so we can set them equal to each other and solve for a:
(a - 1)/1.1 = (a + 3)/1.15
1.15 * (a - 1) = 1.1 * (a + 3)
1.15a - 1.15 = 1.1a + 3.3
0.05a = 4.45
a = 89
Answer:
x = 5
Step-by-step explanation:
11 = 4x-9
20 = 4x
20/4 = 4x/4
5 = x
Answer:
87: y = 5
88: y = 0
89: y = -2
90: y = -1/2x + 9
91: y = 2x - 16
92: y = x - 11
Step-by-step explanation:
To find the slope(m): (y1 - y2)/(x1 - x2)
To find the y-intercept:
y = mx + b
Replace m with the slope and x and y with one of the sets of coordinates. Then simplify to get the y-intercept. Use the equation y = mx + b and replace m with the slope and b with the y-intercept to get the equation.
(Sorry if this is a little confusing.)
