Answer:
13 of August,
Explanation:
All of them worked together at day number zero (August 1).
We know that Elvis works every 3rd day
So he will work at:
day 3, day 6, day 9, etc.
We know that Izzy works every 4th day, then she will work at:
day 4, day 8, day 12, etc.
We know that Janaisa works every 6th day, so she will work at:
day 6, day 12, etc.
We just need to find a day where the 3 of them work, this is equivalent to finding a common multiple of the numbers: 3, 4 and 6.
To do it, we can just write the multiples of each one of these numbers and see which one is the first common multiple:
3)
3*1 = 3
3*2 = 6
3*3 = 9
3*4 = 12
3*5 = 15
...
4)
4*1 = 4
4*2 = 8
4*3 = 12
4*4 = 16
...
6)
6*1 = 6
6*2 = 12
So we can see that 12 is a common multiple of the 3 numbers.
Then they will work together 12 days after August 1th.
That would be the 13 of August,