The below figure represent the required circuit diagram.
Given information, The Emf of each cell is equal to 2.16 V and the Emf of circuit is equal to 4.32 V. The current in circuit is calculated by using, I=
4.32
r1+r2+19.6
Use V = E – Ir for each cell. For P, 2=2.16−
4.32r1
r1+r2+19.6
4.32r1
r1+r2+19.6
=0.16 ...... (1) For Q, 1.92=2.16−
4.32r2
r1+r2+19.6
4.32r1
r1+r2+19.6
=0.24 ....... (2) From Equation (1) and (2) we get, r1:r2=2:3