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.

Answer 1

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