So, Amani, having 9 parts to 5 gives us 14 total parts.
1428/14 = 102 animals in each of the 14 parts
Nine parts are antelope.
9(102) = 918 antelope
It doesn't ask, but to help check, 5(102) = 510 wildabeests, and 918 + 510 = 1428
918/1428 = 9/14
510/1428 = 5/14
Boom.