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Question
How many terms are there in the A.P.?
7, 10, 13, ... 43.
Solution
In the given problem, we are given an A.P.
We need to find the number of terms present in it
So here we will find the value of n using the formula, `a_n = a + (n -1)d`
Here, A.P is 7, 10, 13, ... 43.
The first term (a) = 7
The last term `(a_n)` = 43
Now
Common difference (d) = `a_1 - a`
= 10 - 7
= 3
Thus, using the above mentioned formula, we get,
43 = 7 + (n - 1)3
43 - 7 = 3n - 3
36 + 3 = 3n
`n = 39/3`
n = 13
Thus, n = 13
Therefore, the number of terms present in the given A.P is 13
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