Is there any possibility to get pregnant having a sex one day after period?

my friend had sex one day after her period is there any possibilty that she will get pregnant?

Any time you have unprotected vaginal sex it is possible to get pregnant. In this case, it is unlikely. Anybody that is sexually active should clearly understand the answers to all nine of the questions on planned parenthood's teen web page:

http://www.plannedparenthood.org/info-for-teens/pregnancy/am-pregnant-33831.asp