<span>They are finite sums of expressions of the form where a is a constant, x is the variable and k is a non-negative integer</span>
8 * 7 * 6 * 5 * 4 * 3 * 2 * 1
8 = 40320
By Sine Rule,
x/sin30° = 8/sin90°
x/0.5 = 8/1
So x = 4.
I think c and b are correct answers
