Two planes start from Los Angeles International Airport and fly in opposite directions. The second plane starts 1/2 hour after the first plane, but its speed is 80 kilometers per hour faster. Find the airspeed of each plane if 2 hours after the first plane departs the planes are 2920 kilometers apart.
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casey -
The first plane travels for 2 hours at speed F
The second plane travels for 1.5 hours at speed S
We also know that S = F + 80, so here are the equations to solve:
2F + 1.5S = 2920
S = F + 80
So, now simply use substitution to solve
2F + 1.5S = 2920
2F + 1.5(F + 80) = 2920 , now just solve for F
3.5F = 2800
F = 800, now use S = F + 80
S = 880
Hope that helped
The first plane travels for 2 hours at speed F
The second plane travels for 1.5 hours at speed S
We also know that S = F + 80, so here are the equations to solve:
2F + 1.5S = 2920
S = F + 80
So, now simply use substitution to solve
2F + 1.5S = 2920
2F + 1.5(F + 80) = 2920 , now just solve for F
3.5F = 2800
F = 800, now use S = F + 80
S = 880
Hope that helped