Question

六年级数学题 急````

Answer 1

题1.
3:20
=3*5:20*5
=15:100
题2.
(1)
a:b=3:5=18:30
b:c=6:7=30:35
则a:b:c=18:30:35
(2)
a:b=3:4=9:12
b:c=1/4:1/3=3:4=12:16
则a:b:c=9:12:16
(3)
a:b=2:5
b:c=5:8
a:b:c=2:5:8
题3.
小明回答的不对,正确解法为:
甲杯果汁为1/(1+2)=1/3,乙杯果汁为1/(1+3)=1/4
同理甲杯水有1-1/3=2/3,乙杯水为1-1/4=3/4
丙杯果汁与水的重量比为:
(1/3+1/4):(2/3+3/4)
=(4/12+3/12):(8/12+9/12)
=7/12:17/12
=7:17