设需增加x.原来总支出为a.
[0.55a(1+10%)]/a(1+x)≤0.49 ---1式
[0.55a(1+10%)]/a(1+x)≥0.40 ---2式
由1得x≤51.15%
由2得x≥23.47%
23.47%≤x≤51.15%
答:需增加23.47%~51.15%.
设需增加x.原来总支出为a.
[0.55a(1+10%)]/a(1+x)≤0.49 ---1式
[0.55a(1+10%)]/a(1+x)≥0.40 ---2式
由1得x≤51.15%
由2得x≥23.47%
23.47%≤x≤51.15%
答:需增加23.47%~51.15%.