Set this up as
10 = 40 (1/2)t/28
and solve for t in years.
10/40 = (1/2)t/28
log(0.25) = (t/28) log(0.5)
t = 28 log(0.25) / log(0.5) years = 56 years
Test the answer:
56 years = 2(28 years) = 2 half-lives, so the remaining amount should be 1/2 of 1/2 of the initial amount, i.e. 1/4 of the initial amount, and 10 mg = 1/4 of 40 mg.
Answer:
Explanation:
2/7 = 8/28
1/4 = 7/28
The
8+7 = 15 so 15/28 of lawn has been mowed, therefore 13/28 of the lawn is left still to be mowed.
Answer:
Brazil is a South-American country that has political independence from the 19th Century.
Explanation:
Brazil was a Portuguese colony until 19th Century when it gained political and economical independence. It is today one of the leading economies in the region that has democratic leadership, that is independent towards every other country. Political independence of the country is the main reason why we can discuss about Brazil as an independent country.
circle of latitude are unlike circle of longitude which are all great circle with the centre of the earth in the middle as the circle of latitude get get the smaller as the distance from the equator increase the 60th parallel parallel North or South is half as long as the equator so the latitude of a circle but longitude are only half circle
