A DC10 airplane travels 3000 km with a tailwind in 3 hr. It travels 3000 km with a headwind in 4 hr. Find the speed of the plane and the speed of the wind. Use substitution or elimination to solve.

Answer:The speed of plane is 875 km/h and speed of wind is 125 km/hr Explanation: Assuming v the speed of plane and w the speed of wind Then, the overall speed will be given as (v+w) The speed is calculated by the formula; [tex]$\frac{\text { Distance }}{\text { Time }}$[/tex]For tailwind, given distance travelled is 3000 km in 3 hrs Putting the values in the formula; (v+w) =  [tex]$\frac{3000}{3}$[/tex] (v+w) = 1000              ……eqn (1) Similarly, for headwind, given distance travelled is 3000 km in 4 hrs (v-w) =  [tex]$\frac{3000}{4}$[/tex] (v-w) = 750   ……eqn (2) Adding (1) and (2), we get 2v = 1750 v = 875 km/hr putting value in eqn (1), we get: w = 125  km/hr Therefore, the speed of plane is 875 km/h and speed of wind is 125 km/hr.