Question 12

Explanation

Identifying Proportions

Given:

• To charge from $20\%$ to $100\%$ takes $2.5$ hours.
• The percentage charged is $100\% - 20\% = 80\%$.

Now the battery condition is $60\%$.

• The target charge is $100\%$.
• The percentage needed to charge is $100\% - 60\% = 40\%$.

Direct Proportion

Since the charging power is constant, the time required is directly proportional to the percentage charged.

Substitute the values:

Time Conversion

Convert $1.25$ hours into hours and minutes:

Thus, the time required is 1 hour 15 minutes.