ANSWER:

If you know you won’t be back home before the time of that prayer would be over, you must pray on time wherever you’re at, on time. 

when i have to go outside for a class before the azaan for the prayer and there is no way i can make it up before the other prayer( bcoz the gap between asr and maghrib is not vry long, i happen to miss it smetimes), what am i supposed to do, is it sinful that i cme home and pray, given that i make an effort to make it on time but fail smethimes…???