Answer
In the Name of Allah, Most Gracious, Most Merciful.
All praise and thanks are due to Allah, and peace and blessings be upon His Messenger.
In this fatwa:
1- Prophet Muhammad (peace be upon him) allowed combining prayers to make it easy for the Ummah in times of difficulty.
2- If you have a demanding job and there is no break for offering the prayers at their fixed times, it is permissible to combine prayers.
Sheikh Waleed Basyouni answers your question in the following video:
Almighty Allah knows best.
Source: www.faithiq.org