Question
Find:$10^{th}$ term of the $A.P. -40, -15, 10, 35, .....$
✓
Answer
Given $A.P$. is
$-40, -15, 10, 35, .....$
First term (a) = -40
Common difference (d) = second term - first term
$= -15 - (-40)$
$= 40 - 15$
$= 25$
$n^{th}$ term of an $A.P. a_n = a + (n - 1)d$
$10^{th}$ term of $A.P. a_{10} = -40 + (10 - 1)25$
$= -40 + 9 \times 25$
$= -40 + 225$
$= 185$
$-40, -15, 10, 35, .....$
First term (a) = -40
Common difference (d) = second term - first term
$= -15 - (-40)$
$= 40 - 15$
$= 25$
$n^{th}$ term of an $A.P. a_n = a + (n - 1)d$
$10^{th}$ term of $A.P. a_{10} = -40 + (10 - 1)25$
$= -40 + 9 \times 25$
$= -40 + 225$
$= 185$
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