def simple_interest_pv(V_t, r, t):
    """The present value of a simple interest product tries to find the initial sum whose value at time t is given.
    Also called discounted value.

    Parameters
    ----------
    V_t: float
        Future value at time t.
    r: float
        Interest rate
    t: float
        Time, expressed in years.
    """
    return V_t * (1/(1 + t * r))