Several students are cleaning cars. they charge $4 for washing and $4 for vacuuming. both forms of cleaning take the same amount of time. they have time to clean 20 cars. they want to raise a total of $80. how many of each types of cleaning should they do? make a system of equations to show the problem. then solve the problem visually or by making a graph.

7

step-by-step explanation:

the answer would be 7

large crystals result from very slow cooling.

evaporation of water: this would produce an evaporite which is a sedimentary rock. like a salt pan in a desert. not possible to have volcanic rocks originate this way.

crystalization in molten earth: slow cooling over time. (hundreds to millions of years)

crystalization at earth's surface: this results in fast cooling. (a few hours to a few months or years)

crystalization from cooling off hot water: that would be a hydrothermal deposit. while associated with volcanics they are not volcanic rocks themselves and usually occur fairly rapidly.

x=25?

i think this is the answer hope this

step-by-step explanation: