Question 1023212
Call their scores a, b, and j.  We can write
a = b + 11  (or b = a - 11)
a = j - 5   (or j = a + 5)
a + b + j = 87
Now substitute and get
a + (a-11) + (a+5) = 87
3a - 6 = 87
3a = 93
a = 31 points