1. 4x=64
x=26
2. 9x=20
x=9/20
3. 8+5x<70
5x<62
x<12.4
4. 2+x=50
x=52
5. n+5-5<15
n<15
6. x-10=30
x=40
7. x+5=13
x=8
8. a+8=20
a=12
9. x·3=27
x=9
10. x²=2+6
x²=8
x=√8
x=-√8
Answer:
Length = 150 yards
Width = 100 yards
Step-by-step explanation:
We want 600 yards of fencing that will result in the largest 2 fenced corrals, sharing a common border.
It will take the shape of a rectangle, with a dividing fence down the center.
Let W and L, Width and Length of the larger enclosure.
See attachment.
W= Area of the larger enclosure.
The perimeter is 2W + 2L.
The dividing fence is 1W
We know that we only have 600 yards of fence, so:
2W + 2L + 1W = 600 yards
Area = W x L
---
3W + 2L = 600 (yards)
2L = 600 -3W
L = (600-3W)/2
L = 300 -(3/2)W
---
Use this expression in the Area calculation:
Area = W x L
Area = W x (300 -(3/2)W)
Area = 300W -(3/2)W^2)
To find the maximum area, take the first derivative and set to zero to find the value of W that results in the greatest area.
Area' = 300 -2(3/2)W)
0 = 300 - 3W
3W = 300
W = 100 yards
Since 3W + 2L = 600
L = (600 - 3W)/2
L = (600 - 3(100))/2
L = 150 yards
Area = 150*100 = 15,000 yards^2
One fifth of the participants is 1/5*100=100/5=20 is the number of the participants given medicine. So the number of participants given placebo is 100-20=80.
80% of the 80 who took placebo felt improvements, so 20% of 80, which is
(20/100)*80=(2/10)*80=160/10=16 is the number of participants who took placebo and felt no improvement.
P(choosing participant who took placebo and felt no improvement)=
n(participant who took placebo and felt no improvement)/n(participants)
=16/100=0.16