At 1pm a hospital patient is given a pill containing 60 units of antibiotic. By 2pm the units in the patient’s body has dropped by 15%. By 3pm a further 15% of units remaining in the body is lost. If this fall-off rate is maintained, find the number of units of antibiotic remaining at 6pm.
Here is my calculation: Screenshot
When checking my answer with an online exponential decay calculator I get a different result.
Is my calculation and answer correct?