diff --git a/src/filtering.ts b/src/filtering.ts
index 49411d8..503ce71 100644
--- a/src/filtering.ts
+++ b/src/filtering.ts
@@ -10,9 +10,7 @@ const numbers = [10, 13, 20, 25, 38, 35, 40];
 // example:
 // greaterThanTwentyFive(numbers); // => [38, 35, 40]
 function greaterThanTwentyFive(numbers: number[]): number[] {
-  // write your code here...
-
-  return []; // replace empty array with what you see is fit
+  return numbers.filter((number: number) => number >= 25);
 }
 
 // `divisibleByFive` function that:
@@ -21,9 +19,7 @@ function greaterThanTwentyFive(numbers: number[]): number[] {
 // example:
 // divisibleByFive(numbers); // => [10, 20, 25, 35, 40]
 function divisibleByFive(numbers: number[]): number[] {
-  // write your code here...
-
-  return []; // replace empty array with what you see is fit
+  return numbers.filter((number: number) => number % 5 == 0);
 }
 
 export { greaterThanTwentyFive, divisibleByFive };
diff --git a/src/mapping.ts b/src/mapping.ts
index 6f18eef..63ce94e 100644
--- a/src/mapping.ts
+++ b/src/mapping.ts
@@ -10,9 +10,7 @@ const numbers = [10, 13, 20, 25, 38, 35, 40];
 // example:
 // squaredNumbers(numbers); // => [100, 169, 400, 625, 1444, 1225, 1600]
 function squaredNumbers(numbers: number[]): number[] {
-  // write your code here...
-
-  return []; // replace empty array with what you see is fit
+  return numbers.map((number: number) => number * number);
 }
 
 // `doubledNumbers` function that:
@@ -21,9 +19,7 @@ function squaredNumbers(numbers: number[]): number[] {
 // example:
 // doubledNumbers(numbers); // => [20, 26, 40, 50, 76, 70, 80]
 function doubledNumbers(numbers: number[]): number[] {
-  // write your code here...
-
-  return []; // replace empty array with what you see is fit
+  return numbers.map((number: number) => number * 2);
 }
 
 export { squaredNumbers, doubledNumbers };
diff --git a/src/mapping_filtering.ts b/src/mapping_filtering.ts
index 269ad83..98abfb3 100644
--- a/src/mapping_filtering.ts
+++ b/src/mapping_filtering.ts
@@ -10,9 +10,9 @@ const numbers = [10, 13, 20, 25, 38, 35, 40];
 // example:
 // filteredAndSquared(numbers); // => [400, 625, 1444, 1225, 1600]
 function filteredAndSquared(numbers: number[]): number[] {
-  // write your code here...
-
-  return []; // replace empty array with what you see is fit
+  return numbers
+    .filter((number: number) => number >= 20)
+    .map((number: number) => number * number);
 }
 
 // `filteredAndTripled` function that:
@@ -21,9 +21,9 @@ function filteredAndSquared(numbers: number[]): number[] {
 // example:
 // filteredAndTripled(numbers); // => [30, 60, 75, 105, 120]
 function filteredAndTripled(numbers: number[]): number[] {
-  // write your code here...
-
-  return []; // replace empty array with what you see is fit
+  return numbers
+    .filter((number: number) => number % 5 == 0)
+    .map((number: number) => number * 3);
 }
 
 export { filteredAndSquared, filteredAndTripled };