60 to 30 _ -1/2
30 to 20 _ -1/3
20 to 15 _ -1/4
15 to 12 _ -1/5
12 - (12*1/6) = 10
11
4 15 224 50175 By squaring the previous number minus one
75
There are 15 government departments in Ireland. See the related link below for details.
twenty five
In 1 day 10 men do 1/15 of the work and 15 women do 1/12, so in 1 day working together they would do 1/15 + 1/12 ie 9/60 or 3/20 so it would take 6 and two-thirds days.
The sequence appears to involve two alternating patterns: one decreasing by 1 (15 to 14) and then by 2 (14 to 12), while the last number, 50, seems unrelated to the first three. If we focus on the decreasing pattern, the next number would likely be 11. However, without additional context for the 50, it's unclear how it fits into the sequence. Thus, a possible continuation could be 11 followed by another unrelated number or pattern.
The difference increases by one. 3, 6, 10, 15, 21, 28, 36 and so on.
23, 22, 44, 45. The pattern is minus 2, minus 1, times 2, plus 1, repeat.
number of composite numbers below 20: 10composite numbers below 20: 4, 6, 8, 9, 10, 12, 14, 15, 16, 18
12+12+15+15=54
23