Answer: she scored 69 points on the second test.
Step-by-step explanation:
Let x represent the number of points that she scored in the first test.
Let y represent the number of points that she scored in the second test.
If her mean score was 75, it means that
(x + y)/2 = 75
x + y = 75 × 2
x + y = 150- - - - - - - - - 1
If she scored 12 points more on the first test than the second test, it means that
x = y + 12
Substituting x = y + 12 into equation 1, it becomes
y + 12 + y = 150
2y + 12 = 150
2y = 150 - 12
2y = 138
y = 138/2
y = 69
Answer:
She was paid $55.
Step-by-step explanation:
15%=0.15
8.25/0.15=55
Answer: 1045 cm of red ribbon and 1045 cm of yellow ribbon
<u>Step-by-step explanation:</u>
Let R represent the amount red ribbon and Y represent the amouont of yellow ribbon.
- bought the same lengths of red and yellow: R = Y
- after used 286 of red, yellow is 5 times the remaining red; 5(R - 836) = Y
Use substitution method to solve:
5(R - 836) = R
5R - 4180 = R <em>distributed 5 on the left side</em>
4R - 4180 = 0 <em>subtracted R from both sides</em>
4R = 4180 <em>added 4180 to both sides</em>
R = 1045 <em>divided both sides by 4</em>
Answer: -101
Step-by-step explanation: f(n) = 19-6*n
f(20) = 19 - 6*20
f(20) = -101
A
Step-by-step explanation:First, subtract
2
π
r
2
from each side of the equation to isolate the
h
term:
S
−
2
π
r
2
=
2
π
r
h
+
2
π
r
2
−
2
π
r
2
S
−
2
π
r
2
=
2
π
r
h
+
0
S
−
2
π
r
2
=
2
π
r
h
Now, divide each side of the equation by
2
π
r
to solve for
h
:
S
−
2
π
r
2
2
π
r
=
2
π
r
h
2
π
r
S
−
2
π
r
2
2
π
r
=
2
π
r
h
2
π
r
S
−
2
π
r
2
2
π
r
=
h
h
=
S
−
2
π
r
2
2
π
r
Or
h
=
S
2
π
r
−
2
π
r
2
2
π
r
h
=
S
2
π
r
−
2
π
r
2
2
π
r
h
=
S
2
π
r
−
r
2
r
h
=
S
2
π
r
−
r
