If the common difference of the A.P. is 5, then a18 - a13 is
5
20
25
30
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Given d = 5,
We know that
an = a + (n - 1)d∴ a18 = a + (18 - 1) × 5 = a + 17 × 5 = a + 85. a13 = a + (13 - 1) × 5 = a + 12 × 5 = a + 60.
∴ a18 - a13 = a + 85 - (a + 60) = a - a + 85 - 60 = 25.
Hence, Option 3 is the correct option.
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The 15th term from the last of the A.P. 7, 10, 13, … , 130 is
49
85
88
110
In an A.P., if a18 - a14 = 32 then the common difference is
8
-8
-4
4
In an A.P., if d = -4, n = 7, an = 4, then a is
6
7
28