Respuesta :
Answer:
[tex]7\frac{9}{13}\text{ hours}[/tex]
Step-by-step explanation:
Given,
The number of reports proofread by David in one hour = 15,
While, the number of reports proofread by Armando in one hour = 37,
Total reports proofread by both of them in one hour = 15 + 37 = 52,
Also, the number of reports have to be proofread = 400
Hence, the time taken by both of them when they work together
[tex]=\frac{\text{Total reports}}{\text{Number of reports by both of them in one hour}}[/tex]
[tex]=\frac{400}{52}[/tex]
[tex]=7\frac{9}{13}\text{ hours}[/tex]
