Q 1 :    

In an A.P., if the first term a = 7, nth term an 84 and the sum of first n terms Sn = 2093/2, then n is equal to:

  • 22

     

  • 24

     

  • 23

     

  • 26

     

(3)

Sn=n2(a+an)20932=n2(7+84)

91n=2093n=23

 



Q 2 :    

Which term of the A.P. –29, –26, –23, ..., 61 is 16?

  • 11th

     

  • 16th

     

  • 10th

     

  • 31st

     

(2)

Given, a=-29

d=-26-(-29)=-26+29=3d=3

an=16

Here we know, an=a+(n-1)d

16=-29+(n-1)3

16+29=(n-1)3=15

n-1=453=15

15=n-1n=16



Q 3 :    

The 7th term from the end of the A.P. : – 8, – 5, – 2, ..., 49 is :

  • 67

     

  • 13

     

  • 31

     

  • 10

     

(3)     31

 



Q 4 :    

If k + 7, 2k – 2 and 2k + 6 are three consecutive terms of an A.P., then the value of k is :

  • 15

     

  • 17

     

  • 5

     

  • 1

     

(2)         17

 



Q 5 :    

The common difference of an A.P. in which a15 – a11 = 48, is

  • 12

     

  • 16

     

  • –12

     

  • –16

     

(1)

a15-a11=48

a+14d-a-10d=48

4d=48d=12