The correct answer to this open question is the following.
Although you do not mention what was your week's issue of Studies Weekly to help you answer this question, we can indeed comment on the reason why some Hindus were polytheistic, while others were monotheistic.
Here we go.
Historians and scholars say that in Hinduism, there is a monotheistic conception of divinity but also a polytheistic pantheon of gods for the following reasons.
There is what we can understand as a monotheistic conception of one god in Hinduism. This concept teaches that there is one great mighty god, Hindus call it Brahman. He is the divine force that created everything. So Hindus believe in this original creative force that gave life to everything.
On the other hand, there is a polytheistic approach to Hinduism in that believes that different deities stem from that great Brahman god. We are talking about deities such as Shiva, Ishvara, Hanuman, Ganesha, Vishnu, Vedi, Krishna, Rama, Durga, and Kali, among many others. Hindu pantheon is extensive.
These many gods represented one aspect of creation and Earth, such as the deity of creation and destruction, a deity for knowledge, a deity of dark, a deity of prosperity, and more.
