Answer:
24
Explanation:
If B is number of birds and C is number of cats, then:
B + C = 38
4B + 7C = 194
Two equations, two variables. Solve with substitution or elimination.
Using substitution:
C = 38 − B
4B + 7(38 − B) = 194
4B + 266 − 7B = 194
3B = 72
B = 24
There were 24 birds at the shelter on Thursday.