Answer:
The answer is: 13 minutes
Step-by-step explanation:
First Let us form equations with the statements in the two scenario
Let the time in which the bell rings be 'x'
1. If Andrew walks (50 meters/minute), he arrives 3 minutes after the bell rings. Therefore the time of arrival at this speed = (3 + x) minutes
2. If Andrew runs (80 meters/minute), he arrives 3 minutes before the bell rings. Therefore the time taken to travel the distance = (x - 3) minutes
In both cases, the same distance is travelled, therefore, equation (1) = equation (2)
Next, collecting like terms:
dividing both sides by 3:
x = 390÷30 = 13
∴ x = 13 minutes