Problem $10\mathrm{.}068$E $-$ Air$-$standard dual cycle with constant specific heats

An air$-$standard dual cycle has a compression ratio of $20$ and a cutoff ratio of $1\mathrm{.}150.$ The pressure ratio during the constant$-$volume heat addition process is $1\mathrm{.}2.$ Determine the thermal efficiency, amount of heat added, and the maximum gas pressure and temperature when this cycle is operated at $14$ psia and $70F$ at the beginning of the compression. Use constant specific heats at room temperature. The properties of air at room temperature are

$R=0\mathrm{.}3704a*f\frac{t^3}{l}bm*R,c_p=0\mathrm{.}240Bt\frac{u}{l}bm*R,c_v=0\mathrm{.}171Bt\frac{u}{l}bm*R,$ and $k=1\mathrm{.}4$

The maximum gas pressure is $$ J psia.

The maximum gas temperature is $R.$

The amount of heat added is $$ Btu$/$lbm$.$

The thermal efficiency is $\%.$