Change the mixed number to improper fraction
​

9/5

Step-by-step explanation:

Multiply the number on the side with the denominator: 1*5 = 5

Add the answer to the numerator: 5+4 = 9

since the airplane is moving with constant speed then the distance travelled can be calculated by x=u*t

in km/h would be:

x=640*3.5=2.240 km

in m/s would be:

u=640 km/h= 640.000 m/h =640.000/ 3600 m/s =177.8 m/s

t= 3.5 h= 3.5 * 3600 s=12.600 s

then x=u*t= 177.8*12.600= 2.240.280 m