Consider a turbine engine core. The engine is modeled as ideal. The compressor ratio is $20.$ A fan is fitted to the front of the engine to turn it into a turbofan.

The fan pressure ratio is $1\mathrm{.}7.$ What is the maximum bypass ratio achievable? Ignore the effects of fuel mass flow on turbine power. Use standard conditions

for the compressor inlet and a combustor total temperature of $1500$ K $.$ Hint: assume that no thrust comes from the engine core.

$29\mathrm{.}5$

$9\mathrm{.}3$

$15\mathrm{.}0$

$11\mathrm{.}3$