Question

The sixth term of a sequence is 5. The tenth term is 7.

Which of these position-to-term rules is correct one for the sequence?

A.Term=position number -1
B.Term=2xposition number-7
C.Term=1/2xposition number+2
D.Term=1/6xposition number+4

Answer 1

B term= 2x position number -7

Answer 2

Check the possibilities:

A:

u(n)=n-1

u(6)=6-1= True

u(10)=10-1≠7 False

A is eliminated.

B:

u(n)=2n-7

u(6)=2(6)-7=12-7=5 True

u(10)=2(10)-7=20-7≠7 False

B is eliminated.

C:

u(n)=0.5n+2

u(6)=0.5(6)+2=3+2=5 True

u(10)=0.5(10)+2=5+2=7 True

C is your answer.

Check D although we know it's C:

u(n)=n/6 +4

u(6)=6/6 +4=1+4=5 True

u(10)=10/6 +4=2.5+4=6.5≠7 False