请教一道数学题，看不懂意思....

If the terms of a sequence are t₁,t₂,t₃....t_n, what is the value of n ?

1) The sum of the n terms is 3,124

2) The average(arithmetic mean) of the n terms is 4

题目问你一个数列有几项？

条件1给出数列和

条件2给出数列的平均数

n=和/平均数