seven consecutive odd numbers have an average of 55. what is the biggest odd number in the set
2007-09-03 03:48:37 · 4 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
x= 1st
x+2
x+4
x+6
x+8
x+10
x+12 are the rest
7x+ 42 = 55*7 = 385
7x=343
x=49
So the biggest is 49+12 or 61
2007-09-03 03:58:56 · answer #1 · answered by chasrmck 6 · 0⤊ 0⤋
Let the smallest odd number be 'n'. Then :-
[n+(n+2)+(n+4)+(n+6)+(n+8)+(n+10)+(n+12)]/7 = 55
Removing round brackets and adding we have
[7n + 42]/7 = 55
7n + 42 = 55 x 7 = 385
7n + 42 = 385
7n = 385 - 42 = 343
7n = 343
n = 49 the smallest term.
So n +12 = 49 + 12 = 61 the largest term.
2007-09-03 10:58:49 · answer #2 · answered by lenpol7 7 · 0⤊ 0⤋
(2x+1 +2x+3 + 2x+5 +2x+7+2x+9 +2x+11+2x+13)/7 = 55
(14x+ 49)/7 = 55
14x+49 = 385
14x= 336
x= 24
2x+13 = 61 = largest of the 7 odd numbers
2007-09-03 11:05:17 · answer #3 · answered by ironduke8159 7 · 0⤊ 0⤋
61
2007-09-03 10:54:11 · answer #4 · answered by J S 1 · 0⤊ 0⤋