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
twenty five
There are 15 government departments in Ireland. See the related link below for details.
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 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.
12+12+15+15=54
number of composite numbers below 20: 10composite numbers below 20: 4, 6, 8, 9, 10, 12, 14, 15, 16, 18
23
15 degrees Celsius below 0 is -15 degrees Celsius.