Question 33874
Use the arithmetic sequence of numbers 1, 3, 5, 7, 9,…to find the following:
a)What is d, the difference between any 2 terms? 
d = 3 - 1 = 2

b)Using the formula for the nth term of an arithmetic sequence, what is 101st term?	
a = 1 ;d = 2

Tn = a+(n-1)d
T 101 = 1+(101 - 1)*2
T 101 = 1+100*2 = 201

c)Using the formula for the sum of an arithmetic series, what is the sum of the first 20 terms? 

 Sum of n terms in an A.P is Sn = n/2*{2*a+(n-1)*d}
Here n = 20  ; a =1 ; d = 2

S 20 = 20/2*{2*1+(20-1)*2}
S 20 = 10*{2+38}
S 20 = 10*40 = 400