Problema Solution
lance armstrong can ride 162 miles on flat ground in 6 hours with a good breeze at is back. It takes him 10 hours to go 90 miles with the same breeze working against him. How fast is lance going on a bike and how fast is the wind speed?
Answer provided by our tutors
let
d1 = 162 miles
t1 = 6 h
b = the speed of the breeze
v = the speed of Lance with no breeze
d2 = 90 miles
t2 = 10 h
since speed = distance/time we have
riding with the wind the speed on Lance is: v + b
v + b = d1/t1
v + b = 162/6
v + b = 27
riding against the wind the speed on Lance is: v - b
v - b = d2/t2
v - b = 90/10
v - b = 9
by solving the system of equations
v + b = 27
v - b = 9
we find
v = 18 mph
b = 9 mph
click here to see the step by step solution of the system of equations
the speed of lance is 18 mph.
the wind speed is 9 mph.