Question
Find the third proportional to 15 and
30?Solution
Third proportional = a : b :: b : c It can be written as = b2 = ac  Here, a : b : c = 15 : 30 : c => 30 × 30 = 15 × c => c = (30 × 30)/15 = 60
What should come in place of (?) question mark in the given number series.
5, 9, 17, 33, ?, 129
12    17    44    147    ?   3065   18420
...What value should come in the place of (?) in the following number series?
180, 194, ?, 264, 320, 390
80    81.5    83.5     ?     89      92.5
...- What will come in place of (?), in the given number series.
1, 4, 9, 16, ?, 36 864, 432, 144, ? , 7.2, 1.2
What will come in place of (?) Question mark in the given number series.
1, 2, 5, 14, 41, 122, ?
What will come in place of the question mark (?) in the following series?
10, 135, ?, 226, 234, 235
230 192 172 ? 122 100
...What will come in place of the question mark (?) in the following series?
72, 108, 172, ?, 416, 612
