Having trouble with question 4 can someone

Iwill give brainliest only if your correct the words subsequent and submerge both contain the prefix sub. based on this information, what does the prefix sub most likely mean? a) under or secondary b) true or verifiable c) tricky or difficult d) around or centered on

Strawberries cause two hours per pound kate buys 5 pounds he gets 20% off discount on the total cost how much does kate pay for the strawberries

Idon't get undoing if its pass adding and subtracting so can someone ? x-2 over 5 = 18