With that amount of rest this is designed as a tempo workout(and I probably would have done more). If that's the case then you should be able to run 15:00.
If it wasn't your tempo pace then you should have run a couple seconds faster on each one and taken 2:30 rest. If this is the case then I'll agree with everyone else and say more like 15:30ish
I don't know who designed the workout, but it was kind of pointless unless this is like your last race of the season or something, but then again if you were tapering you wouldn't be running 90 miles this week.
In the one scenario, if you're running 90 miles a week and you're only getting 6k of tempo volume you need to reevaluate your schedule.
On the other hand, if this was supposed to be a Vo2 session, you didn't take nearly enough rest, thus you could have ran the intervals 5-10 seconds faster.