Question 1165482: The 1986 disaster in the former Soviet Union at the Chernobyl nuclear power plant explosion sent about 1000 kg of radioactive
cesium - 137 intc in the atmosphere. The formula A = 1000(0.5)t/30 models the amount (A in kg) of celsium - 137 remaining after
t years in the area surrounding the Chernobyl. How many kilograms of cesium - 137 are still in the atmosphere after 80 years?
a. 639.75 b. 831.24 c. 137.00 d. 157.49
Answer by Theo(13342)   (Show Source):
You can put this solution on YOUR website! the formula is:
A = 1000 * .5 * t / 30.
set t equal to 80 and the formula becomes:
A = 1000 * .5 * 80 / 30.
solve for A to get:
A = 1333.33 rounded to 2 decimal places.
this doesn't look like any of the answers, so something must be wrong with the presentation of the formula.
i changed the formula to read:
A = 1000 * .5 ^ (t/30).
when t = 80, the formula becomes:
A = 1000 * .5 ^ (80/30).
solve for A to get:
A = 157.49.
that would be selection d.
check your formula and make sure you have copied it down correctly.
the symbol for exponentiation is ^
.5 ^ (80/30) means .5 raised to the power of (80/30).
if your formula is what i say it looks like, then selection d is your answer.
if not, then the formula must be something else and an other of the selections could be your answer.
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