Answer:
35 minutes
Explanation:
Let's say that the percentage of the battery's capacity that is charged increases by VVV percent each minute. Then, it increases by V\cdot TV⋅TV, dot, T percent in TTT minutes. In addition, we know that when the charging began, the battery was 232323 percent full.
The percentage of the battery's capacity that was charged at any given time is found by taking the percentage the battery was already charged when the charging began and adding to it the percentage that was additionally charged since then. We can express this with the equation C=23+V\cdot TC=23+V⋅TC, equals, 23, plus, V, dot, T, where:
CCC represents the percentage of the battery's capacity that is charged at a given time
VVV represents the charging rate (in percent per minute)
TTT represents the time (in minutes)
Hint #22 / 4
We know that after 303030 minutes (T=\blue{30})(T=30)left parenthesis, T, equals, start color #6495ed, 30, end color #6495ed, right parenthesis, the battery was 898989 percent full (C=\pink{89})(C=89)left parenthesis, C, equals, start color #ff00af, 89, end color #ff00af, right parenthesis. Let's plug these values into the equation to find the value of VVV.
\qquad \begin{aligned}\pink{89}&=23+V\cdot\blue{30}\\ 30V&=66\\ V&=2.2\end{aligned}
89
30V
V
=23+V⋅30
=66
=2.2
Therefore, the battery was charged at a rate of 2.22.22, point, 2 percent per minute.
Hint #33 / 4
To find how long it took the battery to be fully charged, we can plug C=100C=100C, equals, 100 into the equation and solve for TTT.
\qquad\begin{aligned}100&=23+2.2T\\ 2.2T&=77\\ T&=35\end{aligned}
100
2.2T
T
=23+2.2T
=77
=35
Hint #44 / 4
The battery was charged at a rate of 2.22.22, point, 2 percent per minute.
It took the battery 353535 minutes to be fully charged.