If an island's only residents are penguins and bears, and if there are 14 heads and 30 feet on the island, how many penguins and how many bears are on the island?

Penguins (P): 1 H + 2 Ft

Bears (B): 1 H + 4Ft

Heads Equation:  1P + 1B = 14   → -2(1P + 1B = 14)   →  -2P - 2B = -28

Feet Equation:    2P + 4B = 30 →   1(2P + 4B = 30)  →  2P + 4B = 30

                                                                                               2B = 2

                                                                                                 B = 1

Heads Equation:  1P + 1B = 14   →  1P + 1(1) = 14  →  P = 13

13 Penguins and 1 Bear

$320 to $405

step by step explanation:

in one day he earns between $64 and $81

therefore if he works for 5 days, he will earn between 64 x 5 to 81 x 5

= $320 to $405