题1：某地男性人数比当地总人数的九分之五少四人,女性人数比当地总人数的百分之四十多六人,求当地共有多少人?

题1
设男 = m,女 = f,总人数 = x
m = (5/9)x - 4__i
f = (2/5)x + 6__ii
m + f = x
m = x - f__iii
把 iii 放入 i,
x - f = (5/9)x - 4
f = (4/9)x + 4__iv
用 iv - ii,
0 = (2/45)x - 2
(2/45)x = 2
x = 45
当地有45人.
题2
设第一天 = a,第二天 = b,总书页 = x
a = (1/8)x + 21__i
b = (1/6)x - 6__ii
a + b + 172 = x
a = x - b - 172__iii
把 iii 放入 i,
x - b - 172 = (1/8)x + 21
b = (7/8)x - 193__iv
用 iv - ii
0 = (17/24)x - 187
(17/24)x = 187
x = 264
一共有264页