They will ring again together at 10:15am. Because the common factor for 40, 48 and 60 is 240, which means 240 minutes, that equals to 4 hours. Hence 4 hours after 6.15am is 10.15am.
Hope this helps.
Figure D could be formed from the net.
(bottom right)
-Because-
The net says that the middle shape (the bottom face) is 14 long, and it is 8 tall. So the only option that makes sense is the bottom right!
<em>feel free to mark brainliest! :)</em>
