Question

Find the first term of an Ap whose 25th term is 125 common difference is 2

Answer 1

Step-by-step explanation:

an=a+(n-1)d

125=a+(25-1)2

125=a+24X2

125=48a

a=125/48

Answer 2

Given,

$\[25th\]$ term $\[ = 125\]$

Common difference, $\[\left( d \right) = 2\]$

Solution,

Consider the first term of A.P. is a and common difference is d. Then nth term of the A.P.,

$\[ = a + \left( {n - 1} \right)d\]$

According to the question,

$\[a + \left( {25 - 1} \right) \times d = 125\]$

$\[\begin{array}{l} \Rightarrow a + 24 \times 2 = 125\\ \Rightarrow a + 48 = 125\\ \Rightarrow a = 77\end{array}\]$

Hence the first term of A.P. is $\[77\]$.