Answer
1) 16 kg : 72 kg = 2 : 9
2) 32 g : 40 g = 4 : 5
3) The second gardener has the lowest time taken per bush, the second gardener is the fastest.
Explanation
The first question, writing the ratio 16 kg : 72 kg, in the simplest form
[tex]\begin{gathered} \frac{16}{72} \\ \text{Divide numerator and denominator by 8} \\ \frac{16}{72}=\frac{2}{9} \end{gathered}[/tex]Hence,
16 kg : 72 kg = 2 : 9
2) 32 g : 40 g
[tex]\begin{gathered} \frac{32}{40} \\ \text{Divide numerator and denominator by 8} \\ \frac{32}{40}=\frac{4}{5} \end{gathered}[/tex]32 g : 40 g = 4 : 5
3) We need to write the time taken per bush for each gardener.
[tex]\text{Time taken per bush =}\frac{Time}{Number\text{ of bushes}}[/tex]For the first gardener,
Time = 63 minutes
Number of bushes = 9
Time taken per bush = (63/9) = 7 minutes per bush.
For the second gardener,
Time = 21 minutes
Number of bushes = 7
Time taken per bush = (21/7) = 3 minutes per bush.
For the third gardener,
Time = 25 minutes
Number of bushes = 5
Time taken per bush = (25/5) = 5 minutes per bush.
So, the fastest will be the gardener with the lowest time taken per bush.
So, since the second gardener has the lowest time taken per bush, the second gardener is the fastest.