At a greenhouse, large plants cost $7 and small plants cost $4. Andy purchased a total of 20 plants and pad with a $100 bill. What is the maximum number of large plants that he bought?

Which of the following is an example of an opposing signal? no examplthates given.   i would say, that traffic lights in a city at major intersections direct the flow of traffic in opposite directions so would be an example.also, stop signs on either side of the same street would be an example. at a train crossing, the light for allowing car traffic in opposite directions or not would be another example.