the events are independent. by definition, it means that knowledge about one event does not you predict the second, and this is the case: even if you knew that you rolled an even number on the first cube, would you be more or less confident about rolling a six on the second? no.
an example in which two events about rolling cubes are dependent could be something like:
event a: you roll the first cube
event b: the second cube returns a higher number than the first one.
in this case, knowledge on event a does change you view on event b (and vice versa): if you know that you rolled a 6 on the first cube you don't want to bet on event b, while if you know that you rolled a 1 on the first cube, you're certain that event b will happen.
conversely, if you know that event b has happened, you are more likely to think that the first cube rolled a small number, and vice versa.
let's use x as an unknown variable. you know that this amount was twice what she spent. this statement means the amount is equal to 2x. however, the amount is also 12 dollars less. so, the equation would now become 2x-12. lastly, you know that the amount she spent on jeans was 36 dollars so the equation would equal 36 dollars: 2x-12=36 hope this !