CAS, Mach number, TAS and IAS relationship

Question 1

The local speed of sound decreases with -

Answer 1

Altitude

Question 2

The principle of the Mach indicator is based on the computation of the ratio:

A
(Pt - Ps)/Ps

B
Pt/Ps

C
(Pt - Ps)/Pt

D
(Pt + Ps)/Ps

Answer 2

A

(Pt - Ps)/Ps

Question 3

During a climb, the total pressure probe of the airspeed indicator becomes blocked; if the pilot maintains a constant indicated airspeed, the true airspeed:

A
decreases by 1% per 600 FT

B
increases by 1% per 600 FT

C
increases until reaching VMO

D
decreases until reaching the stall speed