math
posted by Anonymous .
There are three times as many robins as cardinals visited a bird feeder. If a total of 20 robins and cardinals visited the feeder, how many were robins? Must solve using a systems.

r + c = 20
r = 3c
personally, I would not use two variables for a simple one like this
No. of cardinals = x
then robbins = 3x
x + 3x = 20
so easy .... this way