5a + 15 = 24b so,
10a + 30 = 48b,
sub to third equation,
10a + 30 + 35c = 49
10a + 35c = 19
perform elimination with second equation
10a + 45c = 21
10a + 35c = 19
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10c = 2
c = 1/5
sub to second equation,
10a + (45)(1/5) = 21
10a + 9 = 21
10a = 12
a = 6/5
sub to first equation
(5)(6/5) - 24b = -15
6 + 15 = 24b
21 = 24b
b = 7/8
redo the calculations, correct me if I'm wrong