A contractor has two subcontractors for his excavation work. Experience shows that in 60% of the time, subcontractor A was available to do the job, whereas subcontractor B was available 80% of the time. (a) What is the probability that both subcontractors will be available to do the job? (b) If the contractor learned that subcontractor A is not available for the job, what is the probability that the other subcontractor will be available? (c) Suppose EA denotes the event that subcontractor A is available, and EB denotes that subcontractor B is available. (i) Are EA and EB statistically independent? (ii) Are EA and EB mutually exclusive? (iii) Are EA and EB collectively exhaustive?

step-by-step explanation:

i think you should think about the question and not look online.

12

step-by-step explanation:

a triangle's   full angle is 180 degrees so 180 - 156 = 24. 24/2=12

c

step-by-step explanation:

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.