1/9 of the total number of marbles is the same as 1/7 of the total number of paper clips. If there are 245 paper clips, find the total number of marbles.
number of marbles ---- m
number of clips ------ c
(1/9)m = (1/7)c
m/9 = c/7
7m = 9c, but c = 245
7m = 9(245) = 2205
m = 315
or, to avoid large numbers
m/9 = c/7 = 245/7 = 35
m = 9*35 = 315