Theo has $5 more than denise and denise has $11 more than rudy . together , they have $45. how much money does denise have?

T = Theo D = Denise and R = Rudy
Theo has $5 more than Denise T = D + 5
Denise has $11 more than Rudy D = R + 11
Together they have $45 T + D + R = 45

From the information given we have 3 equations. We know the relationship between the variable so we can use substitution and solve.
we need to find D. let rewrite T and R in terms of D then put in the 3rd equation we will have one equation in one variable and we can solve.

T + D + R= 45
(D+ 5) +( D)+ (D - 11) = 45
3D -6 = 45
3D = 51
D = 17

Denise has $17