math
posted by lee .
A jet takes the same time to travel 2500km with the wind as it does to travel 1900 km against the wind. If its speed relative to the air is 450km/hr, what is the speed of the wind?

"same time", so we form an equation by setting the times equal to each other.
2500/(450+x) = 1900/(450x)
cross multiply and solve for x