PREP数学题有点小BT,看不懂啊～～

仙蒂瑞拉

这个是PREP题，可是我看啊看不懂～～～请教！！～～

if the term of a sequence are t1,t2,t3,t4……tn。what is the value of n?

(1)the sum of the n term is 3124

(2)the average of the n term is 4

answer:C

melodyflying

不就是平均数4乘以n=3124吗