Sydney can clean her house in 7.5 hours.
What is Efficiency?
Efficiency is often measured as the ratio of useful output to total input, which can be expressed with the mathematical formula r=P/C, where P is the amount of useful output ("product") produced per the amount C ("cost") of resources consumed.
Here, Monica can clean her house in 5 hours
Monica's efficiency = 1/5
Let, Sydney cleans the house in x hours.
Sydney's efficiency = 1/x
They both together complete their work in 3 hours
Combined efficiency = 1/3
Now, according to question;
1/5 + 1/x = 1/3
(x+5)/5x = 1/3
3x + 15 = 5x
5x - 3x = 15
2x = 15
x = 15/2
x = 7.5
Thus, Sydney can clean her house in 7.5 hours.
Learn more about Efficiency from:
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