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    the question is :
    Calculate the cruise altitude of anGulfstream IV in feet.
    For Gulfstream IV. The following data on this aircraft is given.
    • Number of engines: 2
    • Wing surface: S=88.3 m2
    • Diameter of engine inlet: d=1.1176 m
    • Oswald efficiency: e=0.67
    • Span: b=23.7 m
    • Mass: m=30000 kg
    • (ISA) Air density at cruise altitude: ρ=0.42 kg/m3
    • Cruise speed: VTAS=460 kts
    • Zero-lift drag coefficient: CD0=0.015
    For the International Standard Atmosphere (ISA) please use:
    • Gravity acceleration: g=9.80665 m/s2
    • Gas constant for air: R=287.00 J/ kgK
    • Sea-level pressure: p0=101325 Pa
    • Sea-level temperature: T0=15∘C
    • Sea-level density: ρ0=1.225 kg/m3

    I've tried to solve it as follow:

    P= rho*R*T
    rho is given=0.42
    T means Temperature (it is not given )
    P means pressure
    So I want to get the value of P from the above equation in order to use it in the following equation in order to find the altitude:
    P= rho*h*g
    So I can get the value of h (altitude) h=p/(rho*g)
    but still T in the previous equation is unknown,
    so anyone can help with this question pls
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