Question

help

Answer 1

against the wind
wind will oppose plane and reduce its speed
so effective speed=plane speed-wind speed=280/(1+10/60)=280*6/7=240mph

Answer 2

in direction of wind
wind will support plane and will inc its speed
so effective speed=plane + wind speed=280/(50/60)=280*6/5=336mph
plane-wind=240 .............(1)
plane+wind=336 ...(2)
add (1) & (2)
2*plane=336+240=576
plane=576/2=288mph
wind=288-240=48mph