Answer:
157.5 is the answer
Step-by-step explanation:
Answer:
120 grams will be left after 180 years.
Step-by-step explanation:
A radioactive half-life refers to the amount of time it takes for half of the original isotope to decay and its given by

where,
= quantity of the substance remaining
= initial quantity of the substance
= time elapsed
= half life of the substance
From the information given we know that:
- The initial quantity is 480 g,
- The half-life is 90 years,
- 180 years is the time elapsed.
And we want to find how much will be left. For this we use the above formula.

120 grams will be left after 180 years.
9514 1404 393
Answer:
7 7/8
Step-by-step explanation:
There are several ways to get there.
2.25×3.5 = 7.875 = 7 7/8
(2 1/4)(3 1/2) = (9/4)(7/2) = 63/8 = 7 7/8
(2 1/4)(3.5) = 2(3.5) +(1/4)(3.5) = 7 + (2·3.5)/(2·4) = 7 +7/8 = 7 7/8
A typical graphing calculator will let you enter this problem directly, giving you a result either as a decimal, improper fraction, or a mixed number.