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Match the vocabulary word with its meaning

Geologists know that potassium-40 decays to argon-40, with a half-life of 1.3 billion years. if an analysis of a feldspar crystal in a sample of granite shows that 75 percent of the potassium-40 atoms have decayed to form argon-40, what is the age of the granite

Alaina wants to decide whether her current cell phone plan is better than a package that another company offers. to compare the two plans, she plotted two lines on a graph, where y represented the total cost of one month’s service and x represented the megabytes of data that she used in a month. which part of the graph will represent the cost per megabyte of data used in each plan?