Can someone help me with this question immediately with an explanation??!! Plsss

Answer:
the number of senors is 150
Step-by-step explanation:
call the number of seniors is a
we have number of juniors is 4/3a
number of sophomores is 3/2*4/3*a=2a
number of freshmen is also =2a
sum of all studens in that school = a+4/3a+4a=950
a=150