Question

5 pancakes can be packed in 1 lunch box. How many lunch boxes are required to pack 20 pancakes?

• A. 5 lunch boxes
• B. 6 lunch boxes
• C. 4 lunch boxes
• D. 7 lunch boxes

Answer 1

The correct option is C 4 lunch boxes

-Total number of pancakes = 20 -Number of pancakes in 1 lunch box = 5
-Number of lunch boxes = ?
-Notice that this is a little different from the problems we solved before. This time we know the number of pancakes in each box, but we don’t know the number of lunch boxes that are required.
-Let’s start taking away 5 pancakes and putting them in lunch boxes.
- Since each step requires us to take away 5 pancakes to pack one lunch box, each step will represent 5 pancakes reducing from the number of pancakes that are remaining.

-Step 1: 20 - 5 = 15
- Step 2: 15 - 5 = 10
- Step 3: 10 - 5 = 5
- Step 4: 5 - 5 = 0

- After the 4th step, there are no more pancakes left.
- In each step, 1 lunch box is added to pack 5 pancakes.
- So after 4 steps, 4 lunch boxes will be required.
Hence, option D is correct.