JAMB - Mathematics (2000 - No. 4)
In a youth club with 94 members, 60 like modern music, and 50 like traditional music. The number of members who like both traditional and modern music is three times those who do not like any type of music. How many members like only one type of music?
8
24
62
86
Giải thích
x = no. of ppl that like none.
no. of ppl that like both Traditional and Modern music, which is equal to 3x
Modern Music = 60 - 3x
Traditional Music = 50 - 3x
60-3x + 50 - 3x + 3x + x = 94
110 - 3x + x = 94
-2x = 94 - 110
=>-2x = -16,
this x = 8.
Members that like only one music:
= 60 - 3x + 50 - 3x
= 60 - 3[8] + 50 - 3[8]
= 60 - 24 + 50 - 24
= 36 + 26 = 62
Members that like only one type of music = 62