The identical twins Speedo and Goslo join a migration from the Earth to Planet X$,16\mathrm{.}5$ ly away in a reference frame in which both planets are at rest. The twins, of the same age, depart at the same moment on different spacecraft. Speedo's spacecraft travels steadily at $0\mathrm{.}925$c and Goslo's at $0\mathrm{.}720$c$.$

$($a$)$ Calculate the age difference between the twins after Goslo's spacecraft lands on Planet X$.$

$5\mathrm{.}4$

$4\mathrm{.}05$

Your response differs from the correct answer by more than $10\%.$ Double check your calculations. yr

$($b$)$ Which twin is older?

Speedo Goslo$$