Solution
= Solution
Reducing the <gravitational constant> decreases $H$ at fixed temperature. The <helium sensitivity to the expansion rate> has two effects: weak interconversion persists to a lower freeze-out temperature, leaving fewer neutrons, and the universe takes longer to reach the deuterium-burning temperature, allowing more <free-neutron decay after freeze-out>. \b[Both lower the helium-4 abundance.] In particular $T_f\propto G^{1/6}$ and $t(T)\propto G^{-1/2}$.