Answer:
- trumpeter swans = 41
- sandhill cranes = 26
- mountain chickadees = 164
- ducky grouses = 82
Step-by-step explanation:
Total number of birds = 313
- trumpeter swans = s
- sandhill cranes = c
- mountain chickadees = m
- ducky grouses = g
We have equations below based on given:
s = c + 15
- m = 2g ⇒ m = 2(2s) = 4s ⇒ m = 4(c + 15)
- g = 2s ⇒ g = 2(c + 15)
- s + c + m + g = 313
Substituting m, g and s as above in the last equation and finding the value of c:
- c + 15 + c + 2(c + 15) + 4(c + 15) = 313
- 7(c + 15) + c = 313
- 7c + c + 105 = 313
- 8c = 313 - 105
- 8c = 208
- c = 208/8
- c = 26
Then finding the other values:
- s = 26 + 15 = 41
- g = 2s = 2*41 = 82
- m = 2g = 2*82 = 164
