find the sum of the first 111 terms of an A.P whose 56th term is 5/37.
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[tex]\frac{S_{111}}{111} = \frac{a_{1}+a_{2}+ a_{3}+.....+a_{111}}{111} = a_{56} \\ \\
S_{111} = 111 \times a_{56} = 111 \times \frac{5}{37} = 15[/tex]
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HI there !
No: of terms = n = 111
a₅₆ = 5/37 => a + 55d = 5/37
Sn = n/2 × [ 2a + [ n - 1 ] d ]
= 111/2 × [ 2a + 110d ]
= 111/2 × 2 [ a + 55d ]
= 111 [ a + 55d ]
= 111 × [ 5/37 ]
= 15
sum of 111 terms is 15
No: of terms = n = 111
a₅₆ = 5/37 => a + 55d = 5/37
Sn = n/2 × [ 2a + [ n - 1 ] d ]
= 111/2 × [ 2a + 110d ]
= 111/2 × 2 [ a + 55d ]
= 111 [ a + 55d ]
= 111 × [ 5/37 ]
= 15
sum of 111 terms is 15
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