# TCS Questions on Series and Progressions with Answers -1

1.How many odd and even numbers are there between 42 and 400?? Find the sum of odd numbers and the sum of even numbers!
a.39338
b.33214
c.45321
d.12321
Explaination:
Odd numbers are from 43 to 399. Number of odd numbers = (l−a)/d+1= 399−43/2+1=179
Their sum =n/2(l+a)= 39559
Even numbers are from 44 to 398. Number of even numbers =(l−a)/d+1=(398−44)/2+1=178
Their sum =178/2(398+44)=39338

2.In a staircase, there ar 10 steps. A child is attempting to climb the staircase. Each time she can either make 1 step or 2 steps. In how many different ways can she climb the staricase?
a.10
b.21
c.36
d.None of these
Explaination: Use fibonnacci series, with starting two terms as 1, 2. So next terms are 3, 5, 8, 13, 21, 34, 55, 89

3. Find the average of the terms in the series 1-2+3-4+5….+199-200
a.-0.1
b.-0.2
c.-0.5
d.-0.3
Explaination:(1-2) +(3-4) + (5-6) +……..(199-200) = -100
Average = 100 / 200 = -0.5

4.A series 1234123441234441234444…..n what is the value on 200th position..??
a.1
b.2
c.3
d.4