Answer:
Wyzant
Question
Flying against the wind, an airplane travels 4200 km in 7 hours. Flying with the wind, the same plane travels 4000 km in 4 hours. What is the rate of the plane in still air and what is the rate of the wind?
Answer · 1 vote
Let Va = the velocity of the airplane Let Vw = the velocity of the wind When flying with the wind: (Va+Vw)*(4 hours) = 4000 4Va + 4Vw = 4000 4Vw = 4000 - 4Va Vw = 1000 - Va When flying against the wind: (Va-Vw)*(7 hours) = 4200 km7Va - 7Vw = 4200 Substitute 1000-Va for Vw and solve for Va: 7Va - 7(1000-Va) = 4200 7Va -7000 + 7Va = 4200 14Va = 11200 Va = 800 km/hr Rate of wind: Vw = 1000 - Va = 1000 - 800 = 200 km/hour
More
Socratic
Question
Flying against the wind, an airplane travels 4500 in 5 hours. Flying with the wind, the same plane travels 4640 in 4 hours. What is the rate of the plane in still air and what is the rate of the wind?
Answer · 0 votes
The speed of plane in still air is 1030 km/hr and wind
Step-by-step explanation:
Answer:
- 30/91
Step-by-step explanation:
Answer:
b. (1, 3, -2)
Step-by-step explanation:
A graphing calculator or scientific calculator can solve this system of equations for you, or you can use any of the usual methods: elimination, substitution, matrix methods, Cramer's rule.
It can also work well to try the offered choices in the given equations. Sometimes, it can work best to choose an equation other than the first one for this. The last equation here seems a good one for eliminating bad answers:
a: -1 -5(1) +2(-4) = -14 ≠ -18
b: 1 -5(3) +2(-2) = -18 . . . . potential choice
c: 3 -5(8) +2(1) = -35 ≠ -18
d: 2 -5(-3) +2(0) = 17 ≠ -18
This shows choice B as the only viable option. Further checking can be done to make sure that solution works in the other equations:
2(1) +(3) -3(-2) = 11 . . . . choice B works in equation 1
-(1) +2(3) +4(-2) = -3 . . . choice B works in equation 2