I assume that you have only one global queue, there are 4 cores in total, cores are assigned (if more than one is idle) from 1/1 to 2/2, and the context switch times are 0:
Process # core # start end remaining acc. waiting time
1 1/1 0 5 0 0 *
2 1/2 0 5 1 0
3 2/1 0 5 2 0
4 2/2 0 5 3 0
5 1/1 5 10 4 5
6 1/2 5 10 5 5
2 2/1 5 6 0 0=0+0*
3 2/2 5 7 0 0=0+0 * (core became idle)
4 2/1 6 9 0 1=0+1 * (core became idle)
5 1/1 10 14 0 5=5+0 *
6 1/2 10 15 0 5=5+0 *
*
marks the final accumulated waiting time.