the first and last terms. of A.P are -4 and 146 respectively. and sum of the A.P is 7171 . find the number of terms in A.P and common difference
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Answered by
9
a = - 4
L = 146
Sn = 7171
=> n/2 ( a + L) = 7171
=> n/2 ( - 4 + 146) = 7171
=> n/2 × 142 = 7171
=> n × 71 = 7171
=> n = 101
Number of terms = 101
Now,
L = a + (n-1)d
=> 146 = - 4 +(101 - 1)d
=> 150 = 100d
=> d = 3/2
L = 146
Sn = 7171
=> n/2 ( a + L) = 7171
=> n/2 ( - 4 + 146) = 7171
=> n/2 × 142 = 7171
=> n × 71 = 7171
=> n = 101
Number of terms = 101
Now,
L = a + (n-1)d
=> 146 = - 4 +(101 - 1)d
=> 150 = 100d
=> d = 3/2
Nagavenin:
how 101 as come
plz answer
n × 71 = 7171 => n = 7171 / 71 => n = 101
how 101 its 11 right
no its 101
thats only how
what?
how 101 come if we ÷7171/71
check it using calculator
Answered by
3
a = - 4
L = 146
Sn = 7171
=> n/2 ( a + L) = 7171
=> n/2 ( - 4 + 146) = 7171
=> n/2 × 142 = 7171
=> n × 71 = 7171
=> n = 101
Number of terms = 101
Now,
L = a + (n-1)d
=> 146 = - 4 +(101 - 1)d
=> 150 = 100d
=> d = 3/2
hope it helped ⚡
braínlíest please ❤️
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