When might an egoist believe that it was morally right to sacrifice his own needs and desires for someone else?

Only when it's in his own best-interests to do so, meaning when the reward will outweigh the sacrifice. Egoist tends to be really easy to predict because they only interested in doing something that will give the best possible outcome for them. In this particular context, the egoist may do the sacrifice to obtain wealt or fame

All you have to do is pee in some of the number so that's between x 3 the p is like the prime number so i'll let you do is check for primus pride i've been 7 3 4 5 and 6 and you can you can just times or / that