The half-life of isotope X is 2.0 years. How many years would it take for a 4.0mg sample of X to decay and have only 0.50 mg of it remain

After 2.0 years, the 4.0 mg sample decays to 2.0 mg.

After another 2.0 years (total 4.0 years), the 2.0 mg sample decays to 1.0 mg.

And after another 2.0 years (total 6.0 years), the 1.0 mg sample decays to 0.50 mg.

So it takes 6.0 years for 4.0 mg to decay to 0.50 mg.

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step-by-step explanation:

an equation by definition has to have two or more variables (x and 2 in this case)

answer: 7 x 2/5 = 2.8 hours, is your answer. your welcome! : 3

step-by-step explanation: first work out how long it took to hose 1/7 of the lawn which is 2/5 hours. times that by 7 to get the whole lawn.

sorry i don't know the other answer. i didn't learn what a proportional relationship is.