options 1]163
2]153
3]183
4]203
it is a series .can you solve?
2006-09-08 02:54:41 · 5 answers · asked by sim 2 in Science & Mathematics ➔ Mathematics
5
9=5*2-1
21=9*2+3
37=21*2-5
81=37*2+7
see the pattern
so the next number must be
81*2-9
=153
Answer is 2) 153
2006-09-08 02:58:47 · answer #1 · answered by A 4 · 4⤊ 0⤋
the way to do these is to write the DIFFERENCES and then work your self up again:
5, 9, 21,37,81 the differences will be
..4..12.16..44 then difference again
....8...4...28
......-4..24
.........28
This usually works, but here it suggests that there are alternating signs. (coz of -4 and 24)
so try the first approach
2006-09-08 10:32:46 · answer #2 · answered by blind_chameleon 5 · 0⤊ 0⤋
2. 153
2006-09-08 10:15:44 · answer #3 · answered by Mann 2 · 0⤊ 0⤋
the answer is option 2
2006-09-08 10:02:29 · answer #4 · answered by BoyBlu19 2 · 0⤊ 1⤋
145 BY USING gp
2006-09-09 02:55:03 · answer #5 · answered by free aung san su kyi forthwith 2 · 0⤊ 0⤋