Question

Find the common different of an ap if (a18 — 813 )= 25

Answer 1

hello..
question: Find the common difference of an ap if (a18 — a13 )= 25
now,
a18 = a + (18-1) d= a+17d
&
a13 = a+(13-1)d= a+ 12d
now,
a18 - a13= (a+17d) - (a+ 12d)= 5d= 25
=> d= 5 answer

Formula used: An = a+ (n-1)d

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