Respuesta :
Answer:
31.5 minutes only
Inverse proportion
Step-by-step explanation:
It takes 45 minutes for Laura to mow the lawn.
For Kelly it takes 1 hour 45 minutes or 60+45 = 105 minutes
In one minute Laura can mow 1/45 of the lawn.
Similarly in one minute Kelly can mow 1/105 of the lawn
Together in one minute they can mow the sum
= [tex]\frac{1}{45} +\frac{1}{105}[/tex]
Take lcd for 45 and 105 and make them equivalent fractions with same denominator
LCD of 45 and 105 is 15(3) (7) = 315
[tex]\frac{1}{45} +\frac{1}{105}=\frac{7+3}{315}=\frac{10}{315}\\=\frac{2}{63}[/tex]
In other words it would take 63/2 = 31.5 minutes only to lawn if they work together.
The situation here is the problem on inverse proportion. If no of people increase, work time would decrease.
