1 7200(1-x)^2=3528
(1-x)^2=3528/7200 = 49/100
1-x= ±7/10
x=30% (x=1.7不符题意,舍去)
2 设每次升价百分率为x,设原价为a,则
a(1+x)^2=1.2a
1+x=√1.2 (负值舍去)
x=√1.2 -1 ≈9.5%
1 7200(1-x)^2=3528
(1-x)^2=3528/7200 = 49/100
1-x= ±7/10
x=30% (x=1.7不符题意,舍去)
2 设每次升价百分率为x,设原价为a,则
a(1+x)^2=1.2a
1+x=√1.2 (负值舍去)
x=√1.2 -1 ≈9.5%