(a+b)/5 = (b+c)/7
7(a+b) = 5 (b+c)
7a + 7b = 5b +5c
7a +2b = 5c
(a+b)/5 = (c+a)/8
8(a+b) = 5(c+a)
8a + 8b = 5c +5a
3a +8b =5c
7a + 2b = 3a +8b
4a = 6b
2a = 3b
b = 2a/3
(b+c)/7 = (c+a)/8
8(b+c) = 7(c+a)
8b + 8c = 7c + 7a
c = 7a - 8b= 7a - 8·2a/3 = 5a/3
5a + 2a + 10a/3 = 62
15a + 6a + 10a = 186
31a = 186
a = 6
b = 4
c =10