D=20t in function notation

Cara earns a base pay of $1800 per month at a car dealership plus a commission of 6% of her sales. what are caras total earning in a month in which she sells $40000 worth of merchandise

Saline iv fluid bags cost $64.20 for 24, 1000 ml bags from one supplier. a new supplier sells 500 ml bags for $2 each. the hospital uses about 10,000, 1000 ml bags each month. nurses report that about half of the bags are more than half full when they are discarded. if you are going to use only one supplier, which size bag provides the best deal, and how much will you save each month? compare the cost of the new supplier to the current one.

Which number line correctly shows 0.8 + 0.3?