回答:
#A = 2.3#
説明:
与えられた:
#A = 115 / 100B "" => "" B = 100 / 115A#
#B = C + 0.5 "" => "" C = B-1/2#
#A + B + C = 5.8#
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Cの代わりに
#A + B + C = 5 8/10 "" - > "" A + B +(B-1/2)= 5 4/5#
Bの代わりに
#A B (B 1 / 2) 5 4 / 5 A 100 / 115A 100 / 115A 1 / 2 5 4 / 5#
#A(1 + 200/115)= 5 4/5 + 1/2#
#315 / 115A = 6 3/10#
#A = 2 3/10 = 2.3#