CAT 2020 Percentages — Previous Year Question

Nalini has received a total of $600$ WhatsApp messages from four friends Anita, Bina, Chaitra and Divya. Bina and Divya have respectively sent $30\%$ and $20\%$ of these messages, while Anita has sent an equal number of messages as Chaitra. Moreover, Nalini finds that of Anita’s, Bina’s, Chaitra’s and Divya’s messages, $60\%$, $40\%$, $80\%$ and $50\%$ respectively are jokes. What percentage of the jokes, received by Nalini, have been sent neither by Divya nor by Bina?