Answer:
Friday.
Step-by-step explanation:
The number of bananas is reducing from 23 at a rate of 50% of the previous day's number.
Given that on Monday, Mary had 23 bananas and we are asked that on which day there will be only 1 banana will left.
Let after d days the remaining bananas will become one.
Therefore, [tex]23[1-\frac{50}{100} ]^{d} = 1[/tex]
⇒ [tex](0.5)^{d} =\frac{1}{23}[/tex]
Taking log both sides we get
[tex]d \log 0.5 = \log (\frac{1}{23} )[/tex]
⇒ d = 4.523 days.
Therefore, on Friday the remaining number of bananas will become 1. (Answer)
