Nick, Justin and Clifford collected cards in the ratio of 12 : 4 : 7. After Clifford gave ³₁₀ to Nick and Justin, Clifford had 216 less cards than Nick. The number of cards that Justin had increased by 50%. How many cards did Nick and Clifford have in the end?

	Nick	Justin	Clifford
Before	12 u	4 u	7 u
Change	+ 0.1 u	+ 2 u	- 2.1 u
After	12.1 u	6 u	4.9 u

Number of cards that Clifford gave to Nick and Justin
= ³₁₀ x 7 u
= 2.1 u

Number of cards that Justin received from Clifford
= ⁵⁰₁₀₀ x 4 u
= 2 u

Number of cards that Nick received from Clifford
= 2.1 u - 2 u
= 0.1 u

Number of less cards that Clifford had less than Nick
= 12.1 u - 4.9 u 
= 7.2 u

7.2 u = 216

1 u = 216 ÷ 7.2 = 30

Number of cards that Nick and Clifford had
= 12.1 u + 4.9 u
= 17 u
= 17 x 30
= 510

Answer(s): 510