Question

.
Find the number of terms of the following A.P
(1) 5,8,11,.........95
(2) -5, -8, -11 ............
-230​

Answer 1

Answer:

1) 21 terms

2) 76 terms

Step-by-step explanation:

1) a =5

d= 3

an =95

an= a+(n-1)×d

95=5+(n-1)×3

95-5=3n-3

90+3=3n

93÷3=n

31=n

so,number of term in the A.P is 21

2) a= -5

d=-3

an= -230

an= a+(n-1)×d

-230= -5+[(n-1)×(-3)]

-230+5= -3n+3

-225-3= -3n

-228= -3n

both side is in negative so it is canceled 228=3n

228÷3=n

76= n

so,number of term in the A.P is 76

hope it will help you

Answer 2

Answer:

1. 95=5+(n-1)3

93=3n

n=31

2. -230 = -5+(n-1)-2

-230+5-2=-2n

.. from this u can find n