若1/a+1/b=75%,1/a+1/b+1/c=5/6,则c=_.
问题描述:
若
+1 a
=75%,1 b
+1 a
+1 b
=1 c
,则c=______. 5 6
答
因为
+1 a
=75%,1 b
+1 a
+1 b
=1 c
,5 6
所以
=1 c
-75%=5 6
-5 6
=3 4
,1 12
所以c=12.
故答案为:12.