*MB:
Since M is the centroid of ΔABC, we know that:
MB= 2MD
=> MB= 2 × 13
=> MB= 26
*ME
Since M is the centroid of ΔABC, we know that:
MC= 2ME
=> ME= MC/2
=> ME= 30/2
=> ME= 15
*MF:
Since M is the centroid of ΔABC, we know that:
=> MF= 1/3AF
=> MF= 24/3= 8
(I'm kind of amazed that they don't teach you this rule in your country :))))