In a pet shop, there are only parrots and rabbits. Total heads = 40, and total legs = 100. How many parrots are there?
30
Step 1 – set up equations. Let p = number of parrots and r = number of rabbits.
Heads: \(p + r = 40\).
Legs: parrots have 2 legs, rabbits have 4 legs, so \(2p + 4r = 100\).
Step 2 – solve. From the first equation, r = 40 − p. Substitute:
\(2p + 4(40 - p) = 100 \implies 2p + 160 - 4p = 100 \implies -2p = -60 \implies p = 30\).
Hence, there are 30 parrots.
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