In 2005, 8.1x10^10text messages were sent in the united states. in 2010, the number of annual text messages had risen to 1,863,000,000,000. about how many times as great was the number of text messages in 2010 then 2005?

You must divide the number of text messages in 2010 by the number of text messages in 2005.

Convert the number of text messages in 2010 to scientific notation:

Divide:

23 many times.

Used:

the answer is d

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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.