That's all the square roots of the form 5.xxxx. The numbers start at 5² and end at 6²-1.
So that's 6² - 5² = 11 numbers. We can list them:
25,26,27,28,29,30,31,32,33,34,35
Answer: 11
1/10x + 6 = 2/5x
6 = 2/5x - 1/10x
6 = 4/10x - 1/10x
6 = 3/10x
6 / (3/10) = x
6 * 10/3 = x
60/3 = x
20 = x <=== the gas tank can hold 20 gallons
1/2 is 8/16 in lowest term
