Answer:
The equation is 2x + 5.1 = 11.5
Explanation:
Given that:
Fiona thinks of a number.
Let,
x be that number.
She doubles the number, therefore
2x
Then she adds 5.1 in the number, thus
2x + 5.1
She gets the answer 11.5, so the equation becomes
2x + 5.1 = 11.5
Hence,
The equation is 2x + 5.1 = 11.5