Hi Arix,
You also may want to check documentation about SFPs and QSFPs capabilities, there is a wide number of options.
Based on the output you could use 4x 100gig links (or its variations for breakout connections) and 40x 10gig links. check out the different transceiver modules supported. they will be listed in the proper QFX datasheet.
For example, for a QFX5k
Determining Interface Support for the QFX5100 Device
QFX5100 ETHERNET SWITCH
https://www.juniper.net/assets/us/en/local/pdf/datasheets/1000480-en.pdf
hope it helps.
cheers,
Benjamin