J = K+6
K + J = 4K
<span>Replace J in the second equation </span>
K + (K + 6) = 4K
K + K + 6 = 4K
2K + 6 = 4K
Subtract 2K from each side
6 = 2K
Divide both sides by 2
K=3
<span>So, Keisha is 3 and therefore John is 9 because 3 + 6=9</span>
Since Jones is mandatory, you have 9 people to choose from for the second seat, then 8 for the third, 7 for the fourth, and finally 6 for the fifth.
So your equation is
1(Jones) • 9( possibilities left) •8( possibilities left)• 7( possibilities left)• 6( possibilities left)
Or
1 • 9 • 8 • 7 • 6
=
3,024 possible ways in which a committee of 5 can be chosen from 20 people given that Jones must be one of them.
The answer is D. 28, 14/28 = 1/2.
Hope this helps:)