Fraction Calculation:

To find the fraction of 1 min 20 s that is 45 s, we need to convert all the time units into seconds, and then we can calculate the fraction as follows:

1 min 20 s = 60 s + 20 s = 80 s

Fraction = 45 s ÷ 80 s

Simplify the fraction by dividing both numerator and denominator by 5:

Fraction = (45 ÷ 5) s ÷ (80 ÷ 5) s = 9 s ÷ 16 s

Therefore, the fraction of 1 min 20 s that is 45 s is 9/16.

Explanation:

To solve this problem, we need to understand the concept of fractions and how to convert time units. We know that a fraction is a part of a whole, and it can be represented as a ratio of two numbers. In this case, we want to find the fraction of time that is 45 s out of the total time of 1 min 20 s.

First, we need to convert 1 min 20 s into seconds to make it easier to calculate. We can do this by multiplying the number of minutes by 60 and then adding the number of seconds. So, 1 min 20 s = 60 s + 20 s = 80 s.

Next, we can calculate the fraction by dividing the time duration of 45 s by the total duration of 80 s. This gives us a fraction of 45/80. To simplify this fraction, we can divide both the numerator and denominator by 5, which gives us 9/16.

Therefore, the fraction of 1 min 20 s that is 45 s is 9/16.