Answer:
The speed of sound in air at 700K is 16.8m/s
The Mach number of the aircraft is 20
Explanation:
Speed of sound in air = sqrt(kRT) = sqrt(1.4×0.287×700) = sqrt(281.26) = 16.8m/s
Mach number = velocity of air ÷ speed of sound in air = 340m/s ÷ 16.8m/s = 20 (to the nearest whole number)