it is a lowest common multiple question. So we list the multiples
20 8
<u>40</u> 16
60 24
80 32
<u>40</u>
40 is our lowest common multiple. Which means every 40 minutes they flash and chime together.
so if we add 40 minutes onto 08:00 we get 08:40 and if we add it again we get 09:20 and again we get 10:00 and again we get 10:40 and again we get 11:20 and again we get 12:00. We have to stop here as if we add 40 minutes again we will go over the given time of 12:30. If we count how many times it was added. this adds to 6. therefore the answer is 6.
Again to calculate volume you have to take all three measurements given and multiply them like so: x times y times z. In this case x = 4, y = 1 and z = 18. When you multiply all of these terms you get 72 cubic meters.
