10
Jack has 10
Kathy has 23
Vanessa has 26
10+23+26=59
To solve basically make Jacks money=x
Therefore
Kathys money= x+ 13
Vanessas money= x+13+3 (she has three more than Kathy cause it says Kathy has three less than her)
All of these terms together and make them equal to 59, combine like terms and solve for x (jacks money) which is 10