Question 975475
Let the rate of the jet in still air be x mph
Let the rate of the wind be y mph.
Then we have
x-y=1686/3=562......equation 1
x+y=2136/3=712......equation 2
Adding equations 1 and 2 we get,
2x=562+712=1274
x=637 mph
y=75 mph
The speed of the jet in still air is 637 mph and the rate of wind is 75 mph.