Question
Present average age of 4 friends: ‘A’, ‘B’,
‘C’ and ‘D’ is 24 years. If their ages are in the arithmetic progression in the same order and ‘D’ is 4 years older than ‘B’, then find the sum of present ages of ‘A’ and ‘C’.Solution
Common difference between ages = (4/2) = 2 years. So, let present ages of ‘A’, ‘B’, ‘C’ and ‘D’ be ‘x’, (x + 2) years, (x + 4) years and (x + 6) years, respectively According to question: x + x + 2 + x + 4 + x + 6 = 96 Or, 4x = 84 Or, x = 21 years (Age of A) Present age of ‘C’ = x + 4 = 21 + 4 = 25 years Required sum = 21 + 25 = 46 years
What will come in place of the question mark (?) in the following series?
168, 120, ?, 48, 24, 8
120, 126, 138, 162, ?, 306
In each of the following number series, one term is missing. Find the missing term.
121, 100, 81, ?, 49, 36
84, 105, ?, 168, 210, 259
480, 288, ?, 103.68, 62.208, 37.3248
42, 48, 60, 84, 132, ?
- 8, 12, 18, 27, ?
What will come in place of the question mark (?) in the following number series?
21, 42, 67, 96, ?, 166
11          20          ?             64          112        192
...14, 17, 23, 32, ?, 59
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