Complete the number sequence.
15, 17, __, 28, 30 THe mean of the numbers is 23. What is the missing number?
2007-08-08 11:40:05 · 4 answers · asked by solar 2 in Science & Mathematics ➔ Mathematics
For this sort of problem, you just need to think about it a little. You know that the mean (average) of the numbers is supposed to be 23. You also know that there are 5 numbers. The most intuitive formula would go as follows:
mean = (sum of numbers) / (# of number being averaged)
23 = (15 + 17 + 28 + 30 + x) / 5
and solve for x.
2007-08-08 11:44:16 · answer #1 · answered by Anonymous · 0⤊ 0⤋
23 * 5 = 115 = sum all the numbers
now 115 - (15 +17 + x + 28 + 30 ) = 25
the missing number is 25.
2007-08-08 18:53:10 · answer #2 · answered by salar r 2 · 0⤊ 0⤋
(15+17+X+28+30)/5 = 23
Solve for X
A mean is an average. You know you have five numbers...so the only number you don't know is the X.
2007-08-08 18:43:47 · answer #3 · answered by CG 6 · 0⤊ 0⤋
the mean ins the average so the formula would be
(15+17+28+30+x)=23*5
Soo
90+x=115
x=25
2007-08-08 18:44:20 · answer #4 · answered by Gatlas 3 · 0⤊ 0⤋