# Preferred series & step ratios

Q.  Match the following Group 1 items (Preferred series) and Group 2 items ( Step ratios) and select the correct option

1. R5 ------------------------------------------------ A. 1.12
2. R20 ----------------------------------------------- B. 1.26
3. R80 ----------------------------------------------- C. 1.58
4. R10 ----------------------------------------------- D. 1.03

- Published on 14 Sep 15

a. 1 – D, 2 – C, 3 – A, 4 – B
b. 1 – B, 2 – D, 3 – C, 4 – A
c. 1 – A, 2 – C, 3 – D, 4 – B
d. 1 – C, 2 – A, 3 – D, 4 – B

ANSWER: 1 – C, 2 – A, 3 – D, 4 – B

#### Discussion

• Sravanthi   -Posted on 29 Oct 15
- Series of numbers obtained by geometric progression are called as preferred numbers. The basic preferred series are R5, R10, R20, R40 and R80.

- R5 = 5√10 = 1.58

- R20 = 20√10 = 1.12

- R80 = 80√10 = 1.03

- R10 = 10√10 = 1.26

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