When a runner was crossing the 12 km mark, she was informed that she had completed only 80% of the race. How many kilometres was the runner supposed to run in this event?

Correct Option (2)

Let the total distance of the race be n kilometres.

The problem states that the runner completed 12 km, which constitutes 80% of the total race distance.

This can be mathematically represented as:

0.8n = 12

To determine the total distance n, we solve the equation:

n = 12 / 0.8

n = 15 km

Therefore, the total distance the runner was supposed to run in this event was 15 kilometres.

Incorrect Options:

The other options are incorrect as they do not align with the given condition that 12 km represents 80% of the total race distance.

• If the total distance were 14 km (Option 1), then 12 km would represent approximately 85.7% of the race (12/14 * 100).
• If the total distance were 16 km (Option 3), then 12 km would represent 75% of the race (12/16 * 100).
• If the total distance were 16.5 km (Option 4), then 12 km would represent approximately 72.7% of the race (12/16.5 * 100).

These percentages do not match the specified 80% completion rate.