Question 1183229
The average of m numbers is a and the average of n numbers is b.
 If the average of all the (m+n) numbers is k, what is the value of m
:
the total in 1st group + the total in the 2nd group divided by (m+n) = k
{{{(ma + nb)/(m+n) = k}}}
ma + nb = k(m+n)
ma + nb - km + kn
ma - km = kn - nb
m(a-k) = n(k-b)
:
m = {{{(n(k-b))/(a-k)}}}