Calculate the Exact Number of Parks with 24 Trees Planted

In each park of a city$24.2$ trees are planted on average.

In the first two parks, 19 trees are planted, while in the next three parks 28 are planted.

How many parks planted 24 trees?

To solve this problem, let's calculate step by step:

• Determine the total number of parks: Since all parks combined plant an average of 24.2 trees each, let's assume there are $n$ parks. This implies a total of $24.2n$ trees.
• Calculate trees in known parks: The first two parks have 19 trees each, thus total $2 \times 19 = 38$ trees. The next three parks have 28 trees each, amounting to $3 \times 28 = 84$ trees. Together, they plant $38 + 84 = 122$ trees.
• Set up the equation: Let $x$ be the number of parks that planted 24 trees. Then the rest of the parks account for $24x$ trees. Our equation becomes:

• Express $n$ in terms of $x$:
• Since $n = 2 + 3 + x$ (two parks with 19 trees, three with 28, and the ones we are solving for), we substitute this into the equation:

• Solve for $x$:

Therefore, $\boxed{5}$ parks planted exactly 24 trees. This confirms with answer choice (3).