Step 1: Let each unit of the original ratio represent k stickers. Ahmad originally has 2k stickers. Benny originally has 5k stickers. Step 2: After Ahmad receives 18 more stickers, set up an equation using the new ratio 4 : 5. (2k + 18) : 5k = 4 : 5 Step 3: Cross-multiply and solve for k. 5 × (2k + 18) = 4 × 5k 10k + 90 = 20k 90 = 10k k = 9 Step 4: Find Benny's number of stickers (Benny's count did not change). Benny = 5k = 5 × 9 = 45 Step 5: Verify the new ratio. Ahmad new = 2(9) + 18 = 36 36 : 45 = 4 : 5 ✓ Answer: Benny has 45 stickers.