The 5 th term and 21 st term of a series in A.P are 10 and 42 respectively. Find the 31 st term. Choose the correct choice from the following answers
A) 50  B) 55  C) 65  D) 62  E) 52
a + 4d = 10 ………….. (1)   a + 20d = 42 ………….. (2)   Eqn (2) – Eqn (1) gives 16d = 32 , d = 2   Substituting d =2 in either (1) or (2), a = 2.   31 st term = a + 30d = 2 + 30*2= 
<gadget id="calculator">2 + 30*2</gadget>
<output>62</output>
62   ANSWER:62
<result>D</result>
The 5 th term and 21 st term of a series in A.P are 10 and 42 respectively. Find the 31 st term.