Keenan bought 9 books about plants and 6 books about fish. He also bought 8 science magazines. Each book cost $20 and each magazine cost $3. How much did Keenan spend in all?

answer: when you burn wood, the carbon reacts with the oxygen in the air to create ash and smoke. that is a permanent change you cannot undo that.

step-by-step explanation:

cross multiplying, we get :

⇒ (3) × (5) = (9) × (x)

⇒ 15 = 9x