(1)设每盒有x支笔,
3x+4=40,
3x+4-4=40-4,
3x÷3=36÷3,
x=12,
答:每盒有12支笔;
(2)设女孩高x厘米,
x+25=176,
x+25-25=176-25,
x=151,
答:女孩高151厘米;
(3)设女生有x人,
x+4x=95,
5x=95,
5x÷5=95÷5,
x=19,
19×4=76(人),
答:女生有19人,男生有76人.
(1)设每盒有x支笔,
3x+4=40,
3x+4-4=40-4,
3x÷3=36÷3,
x=12,
答:每盒有12支笔;
(2)设女孩高x厘米,
x+25=176,
x+25-25=176-25,
x=151,
答:女孩高151厘米;
(3)设女生有x人,
x+4x=95,
5x=95,
5x÷5=95÷5,
x=19,
19×4=76(人),
答:女生有19人,男生有76人.