depends on the temp. In the leopard gecko manual it states on pg 74
"anywhere between 36 days at 32.5 c (90.5 F) to 107 days at 24 c (75 F)"
if you keep it at the temp you have now (85F) you'll ahve about a 20% chance for a male and about 80% for male
here's a few good link to check out the hatching process
egg laying, checking to see if they are fertile and hatching