A certain list contains 11 consecutive multiples of 3. The first number is 21. What is the middle number?

If this set contains an odd number of elements, say, 3, 6 and 9, then median of a set will ... as well as the mean of this set, will equal the mean of the two middle elements. ... the statement (1) says: All members of S are consecutive multiples of 3 ... I think the right answer is C, since 9 + 12 + 15 + 18 + 21 = 75

Step-by-step explanation:

We can't write every number as a sum of consecutive numbers - for example, 2, ... the sum is an odd number, e.g. 1+2=3 2+3=5 3+4=7 4+5=9 5+6=11 6+7=13 ... Some spotted a similar pattern for multiples of 3. ... If you add any 3 consecutive numbers together it will always equal a multiple of 3, e.g. ... 1+2+3+4+5+6=21

36

Step-by-step explanation:

11 multiples of 3 starting from 21 - 21, 24, 27, 30, 33, 36, 39, 42, 45, 48, 51

21 is the first

51 is the last

36 is in the middle

it would take 7/10 of an hour too fill the pool.

step-by-step explanation: