Let Daniel's age be 'x' years , hence, Lisa's age is (x - 5) years. Let Grandma's age be 'y' = 54 years.
Hence,
x(x - 5) = 2/3 × y
x² - 5x = 2 × 54 years / 3
x² - 5x = 36 years
x² - 5x - 36 = 0
∆ = (-5)² - 4(1)(-36) = 25 + 144 = 169
√∆ = √169 = 13
x1 = (5+13)/2, x2 = (5-13)/2
x1 = 9, x2 = -4
Since, age can't be negative,
Daniel's age = x = 9 years.
Answer:
-3x + 8
Step-by-step explanation:
Simplify. combine like terms (terms with the same amount of variables).
Subtract -2x and x: -2x - x = -3x
-3x + 8 is your answer.
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Answer:
A. 560
Step-by-step explanation:
multiply 600 by 0.93 in order to find out what 93% of 600 is.
600 x 0.93 = 558
since 558 isn't one of the options you find which one is closest to it, then divide by 600 in order to see if it's still 93%
a) 560/ 600 = 0.93333 = 93.3%
there's your answer.
but to compare it with the rest of the answer choices:
b) 540 / 600 = 0.9 = 90%
c) 470 / 600 = 0.78333 = 78.3%
d) 490 / 600 = 0.81667 = 81.6%
none of these are in the range of 93, so they're incorrect
Answer:
<em>Shayla charges $20 per hour for middle school students and $25 per hour for high school students.</em>
Step-by-step explanation:
<u>System of Equations</u>
Let's call:
x = Shayla's hourly charge for middle school students
y = Shayla's hourly charge for high school students
Last week, Shayla tutored middle school students for 5 hours and high school students for 12 hours. The total earning was 5x+12y. She earned $400 last week, thus:
5x + 12y = 400 [1]
This week, she tutored middle school students for 6 hours and high school students for 10 hours. The total earnings were 6x+10y and it represented $370, thus:
6x + 10y = 370
Dividing by 2:
3x + 5y = 185 [2]
We have formed the system of equations:
5x + 12y = 400 [1]
3x + 5y = 185 [2]
Multiply [1] by -3 and [2] by 5:
-15x - 36y = -1200
15x + 25y = 925
Adding both equations:
-11y = -275
Dividing by -11:
y = -275/(-11) = 25
y = 25
Substituting in [1]:
5x + 12*25 = 400
5x + 300 = 400
5x = 400 - 300 = 100
x = 100/5 = 20
x = 20
Shayla charges $20 per hour for middle school students and $25 per hour for high school students.
