<PRE><B>Question 711438</B>
There are 73 children at the playground.
b + g = 73
g = (73-b)

 1/3 of the boys and 2/7 of the girls are swimming in the pool.
 If there are 22 kids in the pool in all,
{{{1/3}}}b + {{{2/7}}}g = 22
multiply by 21 to get rid of the denominators, resulting in:
7b + 3(2g) = 21*22
7b + 6g = 462
replace g with (73-b)
7b + 6(73-b) = 462
7b + 438 - 6b = 462
7b - 6b = 462 - 438
b = 24 boys at the playground?
:
:
confirm this by finding the number of girls, then the total in the pool.
73 - 24 = 49 girls
{{{1/3}}}*24 + {{{2/7}}}*49 = 
8 + 14 = 22 in the pool</PRE>