Jessica makes photo frames. She spends $5 on the materials for each photo frame. She can create one photo frame in an hour. She earns $10 per hour at a part-time job at the local coffee shop. She can sell a photo frame for $30 each. An economist would calculate the total cost for one photo frame to be.

It would have to be c or d

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.