What is the answer I really need it

We just started the introduction into circles and i have no idea how to do this.

The ph level of a blueberry is 3.1 what is the hydrogen-ion concentration [h+] for the blueberry

Fatima plans to spend at least $15 and at most $20 dollars on sketch pads and pencils. if she buys 2 sketchpads, how many pemcils can she buy while staying in her price range? fatima can buy between and pencils. ? (type whole numbers. use ascending? order.)