Final answer:
An 18-year-old's estimated maximal heart rate is 202 beats per minute, using the formula 220 minus their age.
Step-by-step explanation:
An 18-year-old student's estimated maximal heart rate would be 202 beats per minute. This is calculated using the common formula for estimating maximal heart rate which is 220 minus the individual's age. Therefore, for an 18-year-old, the estimated maximal heart rate would be 220 - 18 which equals 202 bpm.