Question
The ages of 4 members of a family are in the year 2011
are โXโ,โX+6โ,โX+12โ and โX+18โ. After some years Oldest among them was dead then average reduced by 2. After how many years from his death, the average age will same as in 2011?Solution
Average of all in 2011 = {X + (X+6) + (X+12) + (X+18)}/4 = (4X + 36)/4 = X + 9 Let the oldest die after N years, then average of three persons, {X + (X+6) + (X+12) + 3N}/3 = (X+9-2) (3X+18+3N)/3 = X+7 X+6+N = X+7 N = 1 years Let after another M years, their average will be equal to that in 2011. So, (3X+18+3N+3M)/3 = X+9 (3X + 18 + 3x1 + 3M)/3 = X+9 X + 6 +1 +M = X+9 M = 2 years
What will come in place of the question mark (?) in the following series?
1528, 1416, 1204, ?, 480, -32
143 ย ย ย ย 119ย ย ย ย 107ย ย ย ย 101ย ย ย ย ย 98ย ย ย ย ?
96 89 ? 90 94 91
...What value should come in the place of (?) in the following number series?
19, 235, 260, 324, 333, ?
What will come in place of the question mark (?) in the following series?
305...
In each of the following number series, one term is missing. Find the missing term.
3, 5, 20, 24, 144, 150, ?
1029, 1030, 1039, 1064, ?, 1194
75,ย 80,ย 95, ?,ย 155,ย 200
What will come in place of the question mark (?) in the following series?
1515, 184, ?, 455, 967, 624
7 29 61 ? 211 349
...
Relevant for Exams:
