At my favorite fruit stand,
an orange costs 18dollars,
a pineapple costs 27dollars,
and a grape costs 15dollars.
Using the same logic, can you tell

how much a mango costs ?

I am the black child of a white father, a wingless bird, flying even to the clouds of heaven. I give birth to tears of mourning in pupils that meet me, even though there is no cause for grief, and at once on my birth I am dissolved into air.

What am I?

Is there any way of making 7 an even?