Mark gave 21 tadpoles to his 3 friends. Mark gave twice as many tadpoles to David as he did Chris. George received twice as many tadpoles as David. How many tadpoles did each friend receive?

Number of tadpoles Chris has = 3

Number of tadpoles David has = 6

Number of tadpoles George has = 12

Step-by-step explanation:

Given: Total number of tadpoles divided among 3 friends = 21

Number of tadpoles Mark gave to Chris = A

Number of tadpoles Mark gave to David = B = 2A

Number of tadpoles Mark gave to George = C = 2B = 2 (2A) = 4A

∴ Total number of tadpoles = A + B + C

⇒ 21 = A + 2A + 4A

⇒ 21 = 7A

⇒ A = 21 : 7 = 3

∴ Number of tadpoles Chris has = A = 3

Number of tadpoles David has = B = 2A = 2 (3) = 6

Number of tadpoles George has = C = 2B = 2 (2A) = 4A = 4 (3) = 12