Time of Party A: 1 hour 30 minutes+15 minutes = 1.75 hours.
Time of Party B: 1 hour 30 minutes = 1.5 hours.
1.5*3x- 1.75*2x=6
x=6
Speed of a: 2x= 12
Speed of B: 3x= 18
Distance between two places:12 *1.75+18 *1.5 = 21+27 = 48.