Question

Boris has 20 CDs in his music collection. If 20% of the CDs are rock music and 60% of the CDs are pop music, how many CDs are other types of music?

Answer 1

20 CDs total
20% are rock
60% are pop
20 + 60 = 80
100-80=20
Other = 20%
20% of 20 = 4
So, Other = 20% = 4 CD’s

Answer 2

4 Cd's are other types of music.

Explanation:

Hello, I can help you with this,

Step 1

According to the question Boris has 20 CD's , it is our 100%

so.

20 CD ⇔100%

Also, 20% of the CDs are rock music and 60% of the CDs are pop music

20% rock music

60% pop music

x? other types

to find the percentage of other types of music do:

total collection-% rock music-% po music =% other type

100%-20%-60%=20%

so, the 20 % of the collection is of other type of music, let's find how many cds are using a rule of three.

Step 2

if

20 CD ⇔100%

x? ⇔20%

`(20)/(100)=(x)/(20)\\ x=(20*20)/(100)\\ x=(400)/(100)\\ x=4`

so 4 Cd's are other types of music.

Have a good day.