Camera A starts taking pictures at 6 AM and takes a picture every 11 minutes.

Camera A takes picture at 6:55 AM

Camera B takes picture at 7:00 AM

Camera A takes picture at 7:06 AM

lets say that after x times that Camera B takes picture, Camera A also takes picture at the same time as Camera B that is:

7x = 6 + 11y

y = (7x - 6)/11

we need to find the first integer y that satisfies the above equation:

for x = 1, y = 1/11

for x = 2, y = 8/11

for x = 3, y = 15/11

for x = 4, y = 22/11

for x = 5, y = 29/11

for x = 6, y = 36/11

for x = 7, y = 43/11

for x = 8, y = 50/11

for x = 9, y = 57/11

for x = 10, y = 64/11

for x = 11, y = 71/11

for x = 12, y = 78/11

for x = 13, y = 85/11

for x = 14, y = 92/11

for x = 15, y = 99/11 = 9

after 15*7 = 105 min the cameras will take pictures at the same time, for the first time.

the next time (second time) fill happen after:

LCM(11, 7) = 77 min

this means that after 77+105 = 182 minutes Camera A and Camera B will take a picture at the same.

third time after 2*77 + 105 = 259 min

forth time after 3*77 + 105 = 336 min

336 min = 6 hr 36 min after 7 am is 1 pm 36 min.

Camera A and Camera B take their last (forth) picture together 1 hour and 36 min after noon.