(1) THE SUM OF THE FIRST AND SECOND(B) 21TERMS IS ONE-HALF THE SUM OF THE2INCHESTHIRD AND FOURTH TERMS

10, x

1

15, . . .?

(1) The sum of the first and second

(B)

2

1

terms is one-half the sum of the

2

inches

third and fourth terms.

(C)

2

3

(2) The sum of the sixth and seventh

4

inches

terms is 43.

(D) 3 inches