Margo bought 7 pens from a bookstore. some of the pens cost $3 each, and the rest cost $4 each. if she paid a total of $23 for the pens, how many of the $3 pens did she buy? look at picture above for answer choices.

5 Pens!

Step-by-step explanation: 5 Pens Would Be The Answer.

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.