Numbered Disks Are Placed in a Box and One Disk $\frac { 1 } { 2 }$

Multiple Choice

Numbered disks are placed in a box and one disk is selected at random. If there are 6 red disks numbered 1through 6, and 4 yellow disks numbered 7 through 10, find the probability of selecting a yellow disk, given thatthe number selected is less than or equal to 3 or greater than or equal to 8.

A) $\frac { 1 } { 2 }$
B) $\frac { 3 } { 4 }$
C) $\frac { 3 } { 5 }$
D) $\frac { 3 } { 10 }$