Question

The coach asks all the boys from grade 4 to stand in a row. Andrew stands ${10}^{th}$ from the left, while Robert is $9^{th}$ from the right.

The coach asks Andrew and Robert to interchange their positions such that Andrew now stands ${15}^{th}$ from the left.

Find the total number of boys standing in a row.

• A. 24
• B. 25
• C. 26
• D. 23

Answer 1

The correct option is D 23

Position before interchanging:

Andrew = ${10}^{th}$ from the left
Robert = $9^{th}$ from the right

Position after interchanging:

Andrew = $9^{th}$ from the right or ${15}^{th}$ from the left
Robert = ${10}^{th}$ from the left

So, after interchanging their positions, Andrew and Robert's positions can be shown as:


From the above diagram, we can say that 23 boys are standing in the row.