Answer is in the sheet, hope this helps!
It would be the Kelvin Scale.
<u><em>This would be k < 50.</em></u>
This inequality states that k, the price at which Nita wants to buy the new keyboard, is less than 50 dollars.
By Sine Rule,
x/sin30° = 8/sin90°
x/0.5 = 8/1
So x = 4.