Question

Use the substitution method.

In this years bird census, the total number of eagles and condors counted 480. Last year 5 times as many condors and 9 times as many eagles were counted for a total of 3260 birds. How many of each type of bird was counted this spring?

Answer 1

e=number of eagles
c=number of condors

ttoal is 480
c+e=480

5 times as many condors and 9 times as many eagles totals 3260
5c+9e=3260


we have
c+e=480
5c+9e=3260

eliminateion
elmiminate c
times first equation by -5

-5c-5e=-2400

add to other equation

-5c-5e=-2400
5c+9e=3260 +
0c+4e=860

4e=860
divide both sides by 4
e=215

sub back

c+e=480
c+215=480
minus 215 from both sides
c=265


thiis spring is

265 condors
215 eagles