Answer:
C
Sedimentary rocks can be dated using radioactive carbon, but because carbon decays relatively quickly, this only works for rocks younger than about 50 thousand years
Over 2/3 of the argicultural land is used
It changed so much because there were always European explorers heading out on voyages, for many reasons (like to trade with neighbouring countries, ferrying people from one land to the other, etc). During those voyages they found new lands, and so the maps had to be revised quite often because of these new discoveries.
Answer:
Present age of woman = 38 years.
Present age of Daughter = 8 years.
Explanation:
Given :
The sum of the ages of a woman and her daughter = 46 years.
In 4 years time,the ratio of their ages = 7:2.
Solution :
Let assume,
Present age of woman = x years
Present age of Daughter = y years
as given,
The sum of the ages of a woman and her daughter = 46 years.
x+y = 46
x = 46 - y.................(equation 1)
and,
In 4 years time, the ratio of their ages = 7:2.
After 4 years,
Age of woman = (x+4) years
Age of daughter = (y+4) years
→ (x+4) : (y +4) = 7:2
→ x+4/y+4 = 7/2
→ 46-y+4/y+4 = 7/2
→ 50-y/y+4 = 7/2
→7y +28 = 100-2y
→ 7y +2y = 100 -28
→ 9y = 72
→ y = 8
so, y = Present age of Daughter = 8 years.
Put the value of y = 8 in equation (1) .
→ x = 46 - y
→ x = 46 - 8
→ x = 38
Thus, the Present age of woman = x = 38 years.
