find the 60th term of an ap 8,10,12 etc if it has total of 60term and

1.	find the 60th term of an ap 8,10,12 etc if it has total of 60term and hence find sum of its last ten terms
Answer» a=8,d=10-8=2 60th term=a+(60-1)d=8+(59)2=8+118=126 AP:8,10,12.....120,122,124,126 To find sum of last ten terms, reverse the order of AP 126,124,122,120,.....,12,10,8 Now we have to find sum of first ten terms=(n/2)[2a+(n-1)d]=5[2*126+(10-1)(-2)]=5[252-18]=5(134)=670

find the 60th term of an ap 8,10,12 etc if it has total of 60term and hence find sum of its last ten terms

Answer»

a=8,d=10-8=2

60th term=a+(60-1)d=8+(59)2=8+118=126

AP:8,10,12.....120,122,124,126

To find sum of last ten terms, reverse the order of AP

126,124,122,120,.....,12,10,8

Now we have to find sum of first ten terms=(n/2)[2a+(n-1)d]=5[2*126+(10-1)(-2)]=5[252-18]=5(134)=670