A carpenter can do a job in two hours. His assistant can do the same job in three hours. How long would it take them to do the j
2 answers:
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Answer:
(-2, -3)
Step-by-step explanation:
We assume your system of equations is ...
- 2x - y = -1
- 2x -4y = 8
You can subtract the second equation from the first to get
... (2x -y) -(2x -4y) = (-1) -(8)
... 3y = -9 . . . . . collect terms
... y = -3 . . . . . . divide by 3 . . . . this is sufficient to identify the correct answer
Substituting into the first equation, we have ...
... 2x -(-3) = -1
... 2x = -4 . . . . . add -3
... x = -2 . . . . . . .divide by 2
Now, we're sure the answer is (x, y) = (-2, -3).
Answer:
The rate of plane in still air is 834 km/hr and the rate of wind is 80 km/hr.
Step-by-step explanation:
The airplane travels 6032 km in 8 hours against the wind.
So, ........ (1) {Where u is the speed of plane in still air and v is the wind speed}
Again, the airplane travels 7312 km in 8 hours with the wind.
So, ........ (2)
Now, adding equations (1) and (2) we get,
2u = 1668
⇒ u = 834 km per hour.
So, from equation (1), we get
v = u - 754 = 834 - 754 = 80 km per hour.
Therefore, the rate of the plane in still air is 834 km/hr and the rate of wind is 80 km/hr. (Answer)