What was the question for this implicit rationale, and corresponding answer?
The first 8 years cost 8 * 10,000 = $80,000. The next 18 - 8 = 10 years. They cost 10000 * 2 = $20,000 per year. So they cost 20,000 * 10 = $200,000. So the cost was 200,000 + 80,000 = $280,000. Adding in the cost of tuition brings the cost to 250,000 + 280,000 = $530,000. Since John pays for half the cost of raising the child, he pays $530000 / 2 = 265000.
 The answer: 265000
The question: John pays for half the cost of raising a child. It cost $10,000 a year for the first 8 years and then twice that much per year until the child is 18. University tuition then costs $250,000. How much did it cost?