Problem: By adding the same constant to each of 20,50,10020,50,10020,50,100 a geometric progression results. The common ratio is:
Answer Choices:
A. 5/35 / 35/3
B. 4/34 / 34/3
C. 3/23 / 23/2
D. 1/21 / 21/2
E. 1/31 / 31/3 Solution:
Let a=a=a= the constant
20+a50+a=50+a100+a∴a=25∴r=53\dfrac{20+a}{50+a}=\dfrac{50+a}{100+a} \quad \therefore a=25 \quad \therefore r=\dfrac{5}{3} 50+a20+a​=100+a50+a​∴a=25∴r=35​