You should not be struggling with this one. You had better step up your studies. Do NOT forget your basic algebra!
If x = Actuarial Present Value of an n-year term insurance paying $1 at the end of the year of death, and
If y = Actuarial Present Value of an n-year pure endowment of $1, then we have:
750x + 750y = 625
300x + 500y = 300
You need 1000x + 1000y = ??
You can write all the fancy symbols you want, but this is a basic algebra problem.