The average of 1st 3 of 4 numbers is 16 and of the last 3 are 15. If the sum of the first and the last number is 13. What is the last numbers?

let the four numbers be a,b,c,d
Given that
a+b+c= 48 ……I
b+c+d= 45 ……II
adding these two equations we get
a+d+2(c+b) = 93
given that a+d = 13, we get
c+b = 40 Substituting in eq II, we get
d = 5