In the first series, the summation applies to the whole (2n+3) inside
the parentheses, so the 3 gets summed up 5 times.
But in the second one, the summation only applies to the 2n , so
the 3 is only added after the summation is finished.
The difference between five 3s the first time and one 3 the second time
is your 12 .
3/4 is 0.75 as a decimal so 4 x 0.75 = 3
So, to do this, all you need to do is add up all the values, and then, with that number, divide by how many values are given.
150+165+165= 480
480/3= 160
there are 60 minutes in 1 hour, so 1/4 of an hour is 60(1/4), namely 15 minutes.
11:20pm + 4 hours, is 11+4:20, namely 15:20, of course the time system only uses up to 12, so that has to be 3:20, and then we add the 15 minutes.
11+4: 20 + 15.........3:35am.
