For a reaction $\mathrm{A}+\mathrm{B}⟶\mathrm{C}+\frac{1}{5}\mathrm{D}$, kinetics is 5 determined by analysis of partial pressure of gases at different instants. Calculate the value of"a + b + c".

P mm of Hg	t = 0	t = 30 min	t = 60 min
${\mathrm{P}}_{\mathrm{A}}$	20	10	a
${\mathrm{P}}_{\mathrm{B}}$	10000	Not applicable	Not applicable
${\mathrm{P}}_{\mathrm{C}}$	0	Not applicable	15
${\mathrm{P}}_{\mathrm{D}}$	0	b	Not applicable

where a = ${\mathrm{P}}_{\mathrm{A}}$ after t = 60 min b = ${\mathrm{P}}_{\mathrm{D}}$ after t = 30 min c = order of the reaction with respect to A.