Problem: Three numbers a,b,c, none zero, form an arithmetic progression. Increasing a by 1 or increasing c by 2 results in a geometric progression. Then b equals:
Answer Choices:
A. 16
B. 14
C. 12
D. 10
E. 8
Solution:
Since a,b,c are in A.P., 2b=a+c. Since a+1,b,c are in G.P., b2=c(a+1). Similarly, b2=a(c+2).∴c=2a,a=32b,b2=98b2+34b.∴b=12.