Average if between 2 numbers

Question

Trying to find a formula that will look at a column (Column D) for everything after row 7. If the number is between 3.0-3..99 I want to average the number that is in column L starting in Row 7.

So it maybe

Column D
3.2
3.4
5
7
3.9

Column L
250
325
175
100
300

And 1, 2, 5 would be in the range and the average would be $291.66

is there an easy formula that can do this?

thanks!