Initially, Greg has a total of 60 DVDs and CDs in his collection. He then sold 1/8 of his CDs and 1/2 of his DVDs. If the number of DVDs he sold is twice the number of CDs he sold, how many DVDs did he sell?

10 DVD's were sold.

Step-by-step explanation:

c = number of CD's

d = number of DVD's

so we know:

c + d = 60

2*c/8 = d/2

this can be solved:

d = 60 - c

2c / 8 = (60-c)/2

4*(2c/8) = 4*(60-c)/2    [multiply by 4]

c = 120 - 2c

3c = 120

c = 40

d = 60-40 = 20

So Greg had 40 CD's and 20 DVD's. He sold half of his DVD's, i.e., 20/2=10 and 1/8 of his CD, i.e., 40/8 = 5

hope this !

step-by-step explanation:

d = distance between moon and sun, which in this problem is the hypotenuse of a right triangle.  

the distance y is the side opposite to angle x in the right triangle.   use the definition of the sine function from basic trigonometry.

sin(x) = y/d ⇒

d = y/sin(x)

1 1/5

step-by-step explanation: