Exegesis:

aganaktein (cf. 10.14) ‘to be indignant,’ ‘to be angry’: the preposition peri ‘about’ indicates the object of the indignation – ‘to be angry at.’

Translation:

The ten is often translatable as ‘the ten other disciples,’ since in many instances a numeral cannot be used as a substantive, and ‘other’ must contrast the two sets of disciples: the ten versus the two.

Quoted with permission from Bratcher, Robert G. and Nida, Eugene A. A Handbook on the Gospel of Mark. (UBS Handbook Series). New York: UBS, 1961. For this and other handbooks for translators see here .