The half-life of colbalt-60 (used in radiation therapy) is 5.26 years (actual data). how much a of 200 g sample of colbalt-60 will remain after 26.3 years? remaining amount = [ ? ] (1 - [ ] ) ^ []

6.25 grams

Step-by-step explanation:

Since we need to find the number of half-lives in 26.3 years, we simply divide 26.3 yrs by 5.26 yrs which yields 5 half-lives. This means that in 26.3 yrs the 200 grams of cobalt-60 will undergo 5 half-lives.

To obtain the remaining amount we simplify the expression;

A = 200*(1-0.5)^(26.3/5.26)

  = 200*(0.5)^(5)

  = 6.25 grams.

Therefore, the amount of a 200 g sample of colbalt-60 that will remain after 26.3 years is 6.25 grams

452,489 to the nearest thousand is 452,000

76%

step-by-step explanation:

24% are dogs and the remaining is 76% because 100-24=76