Let
x---------> the number of songs that Lou has
y---------> the number of songs that Kelly has
z---------> the number of songs that Tiffany has
we know that
[tex] x+y+z=682 [/tex] ---------> equation [tex] 1 [/tex]
[tex] y=4x [/tex] ---------> equation [tex] 2 [/tex]
[tex] z=6x [/tex] ---------> equation [tex] 3 [/tex]
Substitute equation [tex] 2 [/tex] and equation [tex] 3 [/tex] in equation [tex] 1 [/tex]
[tex] x+[4x]+[6x]=682\\ 11x=682\\ \\x=\frac{682}{11} \\ \\ x=62 [/tex]
Find the value of y
[tex] y=4x\\ y=4*62\\ y=248 [/tex]
therefore
the answer is
Kelly has [tex] 248 songs [/tex]