plzz answer this faast!!
Attachments:
Answers
Answered by
1
S7 = 63
Snext 7 terms = 161
Total number of terms = 7+7 = 14
S14- S7 = Snext 7 terms
S14- 63 = 161
S14= 161 + 63 = 224
S7 = 7/2 ( 2a + d(7-1) )
63 = 7/2(2a + 6d)
Hence on solving you get 2a + 6d = 18 --------equation 1
S14 = 14/2( 2a + d(14-1))
224 = 7(2a + 13d)
2a + 13d = 32 ---------- equation 2
From equation 1 and 2
a = 3 and d = 2
Hence 28th term = a + d(n-1)
= 3 + 2(28-1)
= 3 + 54
= 57
Snext 7 terms = 161
Total number of terms = 7+7 = 14
S14- S7 = Snext 7 terms
S14- 63 = 161
S14= 161 + 63 = 224
S7 = 7/2 ( 2a + d(7-1) )
63 = 7/2(2a + 6d)
Hence on solving you get 2a + 6d = 18 --------equation 1
S14 = 14/2( 2a + d(14-1))
224 = 7(2a + 13d)
2a + 13d = 32 ---------- equation 2
From equation 1 and 2
a = 3 and d = 2
Hence 28th term = a + d(n-1)
= 3 + 2(28-1)
= 3 + 54
= 57
Similar questions