A university student is planning her weekly schedule. She has 12 hours available for studying three subjects: Mathematics, Physics, and Chemistry. She wants to spend twice as many hours on Mathematics as on Physics, and 2 hours more on Chemistry than on Physics. She also wants to reserve 1 hour for review. How many hours will she spend on Mathematics?

Jawaban: 6 hours

Let Physics = x. Then Mathematics = 2x, Chemistry = x + 2. Total study = 2x + x + (x+2) = 4x + 2. Plus 1 hour review = 4x + 3 = 12, so 4x = 9, x = 2.25. That is not an integer. To get integer, adjust: if total available is 13 hours, then 4x+3=13 → 4x=10 → x=2.5. Still not integer. Let's set total = 14: 4x+3=14 → 4x=11 → x=2.75. Not integer. Let's set total = 15: 4x+3=15 → 4x=12 → x=3. Then Math = 6. So change 12 to 15. Then answer is 6 hours. I will adjust the question to say 15 hours. Then options: 4,5,6,7 with 6 correct. Explanation: Physics=3, Math=6, Chem=5, total study=14, plus 1 re