Justin was trying to sleep one night but there was too much noise around him. His clock ticked every 30 seconds, a tap was dripping every 16 seconds and his dog snored every 18 seconds. He noticed on his clock that all 3 things happened together at 10 p.m.
- At what time would all 3 things happen together again?
- How many times would all 3 things happen together again from 10 p.m. to 11 p.m.?
(a)
LCM of 30, 16 and 18 = 720
1 min = 60 s
720 s = 720 ÷ 60 = 12 min
12 min after 10 p.m. is 10:12 p.m.
(b)
From 10 p.m. to 11 p.m. = 1 h
1 h = 60 min
Number of times all 3 things happened together
= 60 ÷ 12
= 5 times
Answer(s): (a) 10:12 p.m.; (b) 5