Let us assume cost of one serving of pancakes = $x
So, the cost of two serving of pancakes = 2 times of x = $2x.
Given cost of the fruit cup = $1.50
Ordered two servings of pancakes and a fruit cup.
Total billed amount = $11.50.
We can setup an equation now,
Cost of two serving of pancakes + cost of the fruit cup + 15%tip = $11.50.
2x + 1.50 + 15% of (2x+1.50) = 11.50.
2x+1.50 + 0.15*(2x+1.50) =11.50
2x+1.50 +0.30x + 0.225 =11.50
Combining like terms
2.30x + 1.725 =11.50
Subtracting 1.725 from both sides
2.30x + 1.725-1.725 = 11.50-1.725
2.30x = 9.775
Dividing both sides by 2.30.
2.30x/2.30 = 9.775/2.30.
On simplifying we get,
x= 4.25.
Therefore, the cost of one serving of pancakes = $4.25.