Numbered disks are placed in a box and one disk is selected at random. If there are 7 red disks numbered 1through 7, and 6 yellow disks numbered 8 through 13, find the probability of selecting a disk numbered 3,given that a red disk is selected.
A) $\frac { 1 } { 7 }$
B) $\frac { 7 } { 13 }$
C) $\frac { 1 } { 13 }$
D) $\frac { 6 } { 13 }$

Question

Numbered disks are placed in a box and one disk is selected at random. If there are 7 red disks numbered 1through 7, and 6 yellow disks numbered 8 through 13, find the probability of selecting a disk numbered 3,given that a red disk is selected. 
A) $\frac { 1 } { 7 }$
B) $\frac { 7 } { 13 }$
C) $\frac { 1 } { 13 }$
D) $\frac { 6 } { 13 }$

Quizplus · Accepted Answer

Given that a red disk is selected, there are 7 red disks to choose from. Only one of these is numbered 3, so the probability is $\frac{1}{7}$.

Numbered Disks Are Placed in a Box and One Disk 17\frac { 1 } { 7 }71​

Numbered Disks Are Placed in a Box and One Disk $\frac { 1 } { 7 }$