Respuesta :

johnstonj59

Answer:

The 21st day

Step-by-step explanation:

If we mark the days, they will clash on the 21st day.

[tex]3*7=21[/tex]

Hope this helped. Have a nice day! Please mark brainliest!

017537

Answer:

if i think u are talking about when these will over lap then they will over lap on the 21st day

Step-by-step explanation: