Given that
1
John can run 100 meters dash in 16 --------- seconds .
5
Savanna 's time is 19.8 seconds .
Here we have John time in mixed fraction and Savanna's time in decimal .
Converting mixed fraction into improper .
1 16 * 5 + 1 80 + 1 81
16 -------- = --------------------------- = -------------- = - -----------
5 5 5 5
Thus we got John time as 81 /5 seconds .
Converting Savanna's time in fraction , we get
19 8
---------- seconds .
10
We have two fractions with different denominator .
One is having denominator 5 and another is having denominator 10 .
We need to make the denominator same of both the fraction .
We need to make denominator 10 .
Multiply John fraction by 2 in both numerator and denominator by 2 to make denominator 10 .
81 * 2 162
---------- = ------------ seconds .
5 * 2 10
John is taking less time than Savanna . Thus John is faster .
Difference
198 162 36
------- - ------- = ------- seconds
10 10 10
Thus John is faster by (36/10 ) seconds = 3.6 seconds .