Mathematics
Two A.P.'s have same common difference. If the difference between their 25th terms is 8, the difference between their 50th terms is :
16
5
8
25
AP GP
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Answer
Let two A.P.'s have first term a1 and a2.
Their common difference be d.
By formula,
⇒ an = a + (n - 1)d
25th term of first A.P. = a1 + (25 - 1)d = a1 + 24d.
25th term of second A.P. = a2 + (25 - 1)d = a2 + 24d.
Given, Difference between 25th terms is 8.
∴ (a1 + 24d) - (a2 + 24d) = 8
a1 - a2 + 24d - 24d = 8
a1 - a2 = 8.
50th term of first A.P. = a1 + (50 - 1)d = a1 + 49d.
50th term of second A.P. = a2 + (50 - 1)d = a2 + 49d.
Difference = (a1 + 49d) - (a2 + 49d) = a1 - a2 = 8.
Hence, Option 3 is the correct option.
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