Question
If x + y + z = 10 and x² + y² + z² = 36, then what is
the value of x y + y z + z x?Solution
(x + y + z) ² = x²+y²+z²+2(x y+y z+z x) (10) ²= 36 + 2(x y+y z+z x) 2(x y+y z +z x) = 64 xy+yz+zx = 32
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
