Beth and Alex have 155p between them.Beth has 15p more than Alex.Beth have x p and Alex have y p. How do I formulate a simulteneous equation

I'm not sure this is a 'simultaneous equation' but this is how i'd solve it.

'p' is just the unit, not a variable, so ignore 'p' for now.

Beth and Alex have 155 between them.

Beth has 15 more than Alex. Beth's amount is represented by x and Alex's amount is represented by y. Since Beth has 15 more than Alex, instead of using x for Beth, use (y+15). Now, Alex is y and Beth is (y+15).

The first equation would be: x + y = 155.

Substituting (y+15) for Beth's x, the new equation is:

y + (y+15)  = 155

Solve for y: 2y + 15 = 155

2y = 140

y = 70

Beth is x, or (y +15), so x = (70+15)

x = 85

Then you can add 'p'. Alex has 70p and Beth has 85p giving 155p in total.