They will need to raise at least 67 tickets because if they sold 66 tickets (15x66) they will only get $990, but if they get 67 tickets (15x67) they'll raise $1005. The easiest way to get the answer fast is to do 1,000 divided by 15 and then see if that number equals 1000, or if you need to add one more ticket to make it at least 1,000.
Answer:
x = 15
Step-by-step explanation:
Assuming 3x and x-60 are in degrees, you can use:
cos(a) = sin(a+90)
To rewrite the equation as:
sin(3x) = sin(x-60+90)
sin(3x) = sin(x+30)
3x = x+30
2x = 30
x = 15
But, solving 3x = x+30 which simplifies to x=15 is not the only solution to this equation, as you can see in below picture. Finding all solutions is a bit more work, but maybe that is not required in your case.
The correct answer is A because the 4 in the X value repeats two time and on the other ones doesn't