"(2) increase in suburbanization" was a direct result of the <span>baby boom that followed World War II, but of course there were other factors that resulted as well. </span>
Answer : The ages of the brother and sister are, 10 and 16 years respectively.
Solution :
Let the age of brother be 'x' and the age of sister be 'y'
There are two equations formed which are,
x + y = 26 ..........(1)
3y - 4x = 8 ..........(2)
First we have to multiple equation (1) by 4 and then added equation (1) and (2), we get the value of 'y'.

Now put the value of 'y' in equation (2), we get the value of 'x'
3(16) - 4x = 8
4x = 40
x = 10
The age of brother = x = 10 years
The age of sister = y = 16 years
Therefore, the ages of the brother and sister are, 10 and 16 years respectively.
B. Fluorine (F) is the right answer
H2O=18.01g/mole. 210g divided by 18.01g/mole=11.653mole. 1 mole has 6.22x10^23 molecules. So there is 11.653x(6.22x10^23) molecules. Just multiply 11.653 by 6.22. Then put it as answerx10^23 molecules