Answer:
Exact form : -31/4
Decimal form: -7.75
mixed number form: -7(3/4)
Step-by-step explanation:
9514 1404 393
Answer:
8
Step-by-step explanation:
The number of days has gone down by a factor of 15/24. The number of workers is inversely proportional, so must increase by a factor of 24/15 = 8/5.
(5 workers) × (8/5) = 8 workers
8 workers are needed to complete the project in 15 days.
Answer:
2 km/h
Step-by-step explanation:
Let x represent the speed of the river current, t₁ be the time spent rowing against the current and t₂ be the time spent rowing with the current.
Since the speed of the still water = 20 km/h.
The speed of rowing against the current = (20 - x)
The speed of rowing with the current = (20 + x)
We know that velocity = distance / time. Hence time = distance / velocity
t₁ = 36 / (20 - x)
t₂ = 22 / (20 + x)
but t₁ + t₂ = 3 hours
Therefore:
3 = 36 / (20 - x) + 22 / (20 + x)
multiply through by 400 - x²
3(400 - x²) = 36(20 + x) + 22(20 - x)
1200 - 3x² = 720 + 36x + 440 - 22x
3x² + 14x -40 = 0
This gives x = -6.7 or x = 2
x cannot be negative therefore x = 2 km/h
The speed of the river current is 2 km/h
Answer:
33 students
Step-by-step explanation:
Fifteen percent of the students in seventh grade at western middle school have perfect attendance. There are 220 students in seventh grade. How many have perfect attendance?
Fifteen percent in decimal from is 0.15.
You would then multiply that by the number of students; 220.
.15 * 220 =
One multiplied, you get 33.
Therefore, 33 students have perfect attendance.
