John is using square ceramic floor tiles that are each 18 inches long. how many of these tiles will john need to cover a floor with an area of 81 square feet? site:

First we need to convert the square feet to square inches

1 square feet = 144 square inches

Therefore, 81 square feet = 81*144 = 11,664 square inch

Each square tile is 18 inches long. Since its a square, the area of each tile = 18*18 = 324 square inch

So,the number of tiles required to cover the entire floor= total area of the floor in square inches/ area of the tile in square inches

The number of tiles required to cover the entire floor = 11,664/324 = 36 tiles

The number of tiles required to cover the entire floor = 36 tiles

linearly: 8560 bacteria

exponentially: approximately 75233 bacteria

step-by-step explanation:

assuming it is not exponential (we would have some really complicated logarithms), let's say it is linear. then, after 5 hours, it increased by 1200 bacteria, so every hour it increases by 240 bacteria. this means that after 19 hours, we get 19 * 240 + 4000 bacteria or 3800 + 760 + 4000 = 7800 + 760 = 8560 bacteria.

because it says round your answer, i will do this exponentially (with a calculator, of course). first, we need to find how much it multiplies by every hour, by taking the 5th root of 52/40 or 13/10. this is approximately 0.167. we still need to add 1 to this, because we are multiplying by that number, not adding that amount of the number. now, we just calculate 4000 * (1.167)^19. use a calculator to get approximately 75232.6, or 75233.

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