Join 60,000+ competitive exam aspirants
or with email
Your Cart
SubtotalтВ╣0
TotalтВ╣0
Examoogle тАв User тАв info@examoogle.com тАв EE-2024-8821
Chapter 1 of 12 тАв Page 1 of 248ЁЯФТ Protected PDF тАв Watermarked
Join 60,000+ competitive exam aspirants
Find the missing number: 5, 10, 20, 40, ?
60
70
80
90
80
Observe the constant ratio between consecutive terms; each number is being multiplied by 2 to get the next number.
Observe the constant ratio between consecutive terms; each number is being multiplied by 2 to get the next number.
Analyze the pattern
Calculate the ratio between consecutive terms: 10/5 = 2, 20/10 = 2, 40/20 = 2. The series follows a geometric progression with a common ratio of 2.
Calculate the missing number
Apply the common ratio to the last given number: 40 multiplied by 2 equals 80.
A: 60 is incorrect because it assumes a constant addition of 20, which fails at the first term. B: 70 is incorrect as it does not follow the geometric ratio of 2. D: 90 is incorrect because it does not result from doubling the previous term of 40.
C is correct because the series follows a consistent geometric pattern where each number is doubled (multiplied by 2) to obtain the subsequent number.
When looking at a series, always check the difference between terms first. If the difference increases rapidly, test for multiplication or squares/cubes instead of simple addition.
Get instant step-by-step AI explanations, full shift Previous Year Papers (SSC GD, RRB, SSC JE), and regional rank analysis on the official Examoogle App.
Free Download тАв 100K+ Aspirants