Question

求教一道数学题~

Answer 1

解:(1/a+1/b+1/c+1/d)+1/36+1/45=1
1/a+1/b+1/c+1/d=1-1/36-1/45
1/a+1/b+1/c+1/d=1-1/20
1/a+1/b+1/c+1/d=19/20
因为a,b,c,d恰好是4个连续自然数,则有
1/a>1/b>1/c>1/d
也就是说4*1/d<19/20
1/d<19/80
d>80/19
d>5
同理:4*1/a>19/20
1/a>19/80
a<80/19
a<4
而a>=2(当a=1时,1/a+1/b+1/c+1/d>1>19/20)

(1)当a=2时,1/a+1/b+1/c+1/d=77/60不等于19/20,不合题意
(2)当a=3时,1/a+1/b+1/c+1/d=57/60=19/20
所以a=3,b=4,c=5,d=6

Answer 2

设B为X，则C=X+1,D=X+2,A=X-1，解方程

Answer 3

a=3,b=4,c=5,d=6

Answer 4

已有答案

Answer 5

A=3 B=4 C=5 D=6