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Solve an exponential equation for radioactivity

"}, "statement": "

The radioactivity of fallout t days after a nuclear explosion is modeled by 

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If the radioactivity is found to be  \\(1/\\var{2^a}\\) of the original amount after \\(\\var{t}\\) days, find the value of \\(k\\)

", "rulesets": {}, "advice": "

\\(\\var{k}=\\var{a}e^{\\var{m}x+{\\var{c}}}\\)

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\\(\\frac{\\var{k}}{\\var{a}}=e^{\\var{m}x+\\var{c}}\\)

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\\(ln\\left(\\frac{\\var{k}}{\\var{a}}\\right)=\\var{m}x+\\var{c}\\)

\n

\\(ln\\left(\\frac{\\var{k}}{\\var{a}}\\right)-\\var{c}=\\var{m}x\\)

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\\(\\frac{ln\\left(\\frac{\\var{k}}{\\var{a}}\\right)-\\var{c}}{\\var{m}}=x\\)

", "ungrouped_variables": ["a", "t"], "functions": {}, "name": "Haifa's new exponential equation to solve for radioactivity", "variables": {"a": {"templateType": "randrange", "name": "a", "description": "", "group": "Ungrouped variables", "definition": "random(1..5#1)"}, "t": {"templateType": "randrange", "name": "t", "description": "", "group": "Ungrouped variables", "definition": "random(2..12#1)"}}, "extensions": [], "tags": [], "preamble": {"css": "", "js": ""}, "parts": [{"prompt": "

Input your answer correct to three decimal places.

\n

\\(k = \\) [[0]]

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