Dahlia bought Granny Smith and Macintosh apples at the grocery store. The Granny Smith apples were $1.35 each if you bought 6. Find the cost of each Macintosh apples if the total cost is $15 and she bought 6 each.
The 6 Granny Smith apples cost $1.35 x 6 = $<<1.35*6=8.1>>8.1.
The 6 Macintosh apples cost $15 - $8.1 = $<<15-8.1=6.9>>6.9.
So, the cost of each Macintosh apple is $6.9/6 = $<<6.9/6=1.15>>1.15. Answer: \boxed{1.15}.