1️⃣ Man + Parrot on his head = 200
2️⃣ Man – Parrot (parrot on the ground) = 170
Man - M
Parrot - P
We have two equations:
(1) M + P = 200
(2) M – P = 170
Add the two equations:
(M + P) + (M – P) = 200 + 170
2M = 370
M = 185
185 + P = 200
P = 15
The parrot’s height is 15 units