Element X is a radioactive isotope such that every 28 years, its mass decreases by half. Given that the initial mass of a sample of Element X is 80 grams, how long would it be until the mass of the sample reached 61 grams, to the nearest tenth of a year?

0.16 or 16%

step-by-step explanation:

lets take a coin for example.

if you toss it twice, it has a 1/4 chance of landing on heads both times because 1/2 * 1/2 is 1/4.

with the cards, the chance of picking dog is 0.4. having two people pick one is like picking a card twice in a row. so 0.4 * 0.4 is 0.16, or 16%

77

step-by-step explanation:

c 1 hour

step-by-step explanation:

m = 2e

m = 2 so 2 = 2e

1 = e

0.6

39mph

step-by-step explanation: