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a)
(1/3-1/5)x1/4 = 1/3x1/4-1/5x1/4=1/12-1/20=1/30
(1/3-1/5)x1/4 = 2/15x1/4=1/30
b)
2/5 x 3/7 + 2/5 x 4/7= 6/35 + 8/35 = 14/35 = 2/5
2/5 x 3/7 + 2/5 x 4/7= (3/7+4/7) x 2/5 = 1 x 2/5 = 2/5
a: C1: (1/3-1/5)*1/4
=2/15*1/4=2/60=1/30
C2: (1/3-1/5)*1/4
=1/3*1/4-1/5*1/4
=1/12-1/20=1/30
b: C1: 2/5*3/7+2/5*4/7
=6/35+8/35=14/35=2/5
C2: 2/5*3/7+2/5*4/7
=2/5(3/7+4/7)
=2/5*1=2/5
`1/2 xx 1/3 xx 1/4`
`= (1xx1xx1)/(2xx3xx4)`
`= 1/24`
__
`1/2 xx 1/3 : 1/4`
`= 1/2 xx 1/3 xx 4`
`= (1xx1xx4)/(2xx3)`
`= 4/6`
`=2/3`
__
`1/2 : 1/3 xx1/4`
`= 1/2 xx 3 xx 1/4`
`=(1xx3xx1)/(2xx4)`
`= 3/8`
__
`1/2 : 1/3 : 1/4`
`= 1/2 xx 3xx4`
`= 12/2`
`=6`
`1/2xx1/3xx1/4`
`=1/24`
`1/2xx1/3:1/4`
`=1/6xx4`
`=4/6=2/3`
`1/2:1/3xx1/4`
`=1/2xx3xx1/4`
`=3/2xx1/4`
`=3/8`
`1/2:1/3:1/4`
`=1/2xx3xx4`
`=6`
x=1