Challenge 2: The Same Dictionary Query, Both LINQ Syntaxes — Possible Solution
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Program.cs:

Dictionary<string, int> ages = new()
{
    ["Alice"] = 30,
    ["Bob"] = 25,
    ["Carol"] = 41,
    ["Dave"] = 19
};

// Method syntax
var methodResult = ages.Where(pair => pair.Value >= 30);

// Query syntax
var queryResult = from pair in ages
                   where pair.Value >= 30
                   select pair;

Console.WriteLine("Method syntax:");
foreach (var pair in methodResult)
    Console.WriteLine($"  {pair.Key}: {pair.Value}");

Console.WriteLine("Query syntax:");
foreach (var pair in queryResult)
    Console.WriteLine($"  {pair.Key}: {pair.Value}");

Output:

    Method syntax:
      Alice: 30
      Carol: 41
    Query syntax:
      Alice: 30
      Carol: 41

Explanation:
Both queries express the identical filter -- age 30 or older -- just
written two different ways. Method syntax chains Where() as a
fluent call; query syntax uses the from/where/select keywords built
directly into C#'s own grammar. Both compile down to equivalent LINQ
calls under the hood, which is why they produce byte-for-byte
identical results here.

WHY THIS WORKS AS AN ANSWER
------------------------------
This writes the same query twice, once in each LINQ syntax the
chapter introduces, over a Dictionary rather than an array or List,
confirming both syntaxes are genuinely equivalent and that LINQ
applies uniformly across different collection types.