F+2/9=9 1/9
F=9 1/9-2/9
F=8 8/9
y- 14/9= 4 1/6
y=4 3/18+28/18
y=5 13/18
Answer:
<u>If P is 30 units and l is 10 units, w is 5 units</u>
Step-by-step explanation:
1. Let's check the information given to resolve the question:
P = 2l + 2w
If P is 30 units and l is 10 units, w is units
2. Replacing with the values:
P = 2l + 2w
30 = 2 (10) + 2w
30 = 20 + 2w
-2w = 20 -30 (Subtracting 2w and - 30 to both sides)
-2w = - 10
2w = 10 (Multiplying by - 1 at both sides)
<u>w = 5 (Dividing by 2 at both sides)</u>
<u>If P is 30 units and l is 10 units, w is 5 units</u>
<u>Note: Same answer than question 13938258</u>
Try this solution:
Answer: 6 & 4.5 (m-per-h)
Step-by-step explanation:
- The basic formula used in this task is S=V*t, where S - distance, V - speed, t - time.
- the downstream speed is: V+Vc, where V - the speed of the boat in still water, Vc - the speed of the current.
- the upstream speed is: V-Vc.
- according to the described above the distance for downstream is S1=(V+Vc)*t1, where t1=10; the distance for upstream is S2=(V-Vc)*t2, where t2=70.
- for whole travel down- and upstream: S=S1+S2.
- Using these it is possible to make up the system of the equations:

V - the speed of the boat in still water - 6 miles per hour, Vc - the speed of the current - 4.5 miles per hour. All the details for the system of the equations are in the attachment.
<h2>D. This is an experiment with blocking </h2><h2 />
For your question: "A teacher wants to investigate whether listening to music while taking a math test increases scores. He instructs half
of his 36 students to listen to music while taking a test and the other half to not listen to music during the test. To
determine who listens and who does not, the teacher identifies the two students who scored highest on the last test
and randomly instructs one to listen to music and one to not. The teacher does the same for the next two highest-
scoring students and continues in this manner until each student has their instructions. Which of the following best
describes this plan?"
The answer is D