Question

In an A. P., the first term is 5 and last term is 60.If sum of all numbers in the A. P. is 195, then how many terms are there? What is the common difference?

Answer 1

Answer:

d=11

Step-by-step explanation:

a=5,l=60

n-?

Sn=n/2*(a+l)

195=n/2*(5+60)

195=65n/2

n=195*2/65=6

l=a+(n-1)d

60=5+5d

5d=55

d=11

Answer 2

a1= 5

l=60

an=195

sn=n/2(a1+l)

195=n/2(5+60)

195= n/2(65)

n=195×2/65

n=6

an=a1+(n-1)d

60=5+(6-1)d

55=5d

d=11