Final answer:
To determine the total donation for a 15-mile bike ride, divide 15 by 0.25 to find the number of 0.25-mile chunks, which is 60. Multiply this by the pledge rate of $0.40 per 0.25 mile to get the total donation of $24.00.
Step-by-step explanation:
The student's question involves calculating the total donation based on a given rate of donation per unit of distance. To find out how much Emily's mother will donate for a 15-mile bike ride, we must first determine how many chunks of 0.25 miles are in 15 miles.
To calculate this, we divide the total miles biked by the size of one chunk:
15 miles ÷ 0.25 miles = 60
Now we know there are 60 chunks of 0.25 miles in 15 miles. Emily's mother pledges $0.40 for every 0.25 mile biked, so we multiply the number of chunks by the amount pledged per chunk:
60 × $0.40 = $24.00
Therefore, for a 15-mile bike ride, Emily's mother will donate $24.00 to charity.