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1)One-fourth of the coins in a bag are $1 coin and the rest are $2 coin. The total value of the coins is $140.a)find the total number of coins in the bagb)find the total value of $2 coin2)If we treble the number of girls in a class and minus 4, we have the number of boys. If the number of boys is 20,find the... 顯示更多 1)One-fourth of the coins in a bag are $1 coin and the rest are $2 coin. The total value of the coins is $140. a)find the total number of coins in the bag b)find the total value of $2 coin 2)If we treble the number of girls in a class and minus 4, we have the number of boys. If the number of boys is 20,find the number of girls.(hint,'treble the number' means'three times a number'. 3)Aaron's present age is x, a)Jacky's age is three times Aaron's.Express, in term of x,Jacky's present age. b)Express,in terms of x,Jacky's age in 10 years. c)Jacky's age will be four times Aaron's present age in 10 years.Write down an equation involving x. d)Solve the equation in(c).Hence find their present ages. 4)Take away one-third of a number and then take away 44.One-seventh of the number remains.Find the number. 5)Divide an amount of money btween Peter,John and Joyce.Peter gets $x. a)John gets $300more than Peter.Express,in terms of x,the amount that John gets. b)Joyce gets $100 more than John.Express, in terms of x,the amount that Joyce gets. c)If the amount of money is $1,300 , hoe much does each get? 6)ABCDE is a pentagon in which ∠A and ∠C are equal and so are ∠B and ∠E.∠A is 67o greater than ∠D,and ∠D is halp of ∠E.Find the angles.(Hint:The angle sum of a pentagon is 540o) 7)A plant has grown by 24% to the height of 186cm in one year. a)what was its height one year ago？ b）If the plant is pruned so that its height is decreased by 12%,find its new height.
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1 let the coins be x 1x/4=40 x=160 160x3/4=120 120x2=240 a 160 coins b $240 2 let the number of girls be x 3x-4=20 x=8 there are 8 girls 3a 3x b 3x+10 c 3x+10=4x d x=10 Aaron,10 years old, Jacky,30 years old 4 let the number be x x-x/3-44=1/7 21x-7x/21=44 14x=21x44 2x=3x44 x=66 the number is 66 5a $(x+300) b$(x+400) c x+x+300+x+400=1300 3x=600 x=200 Peter,$200,John,$500,Joyce,$600 6 let ∠A and ∠C be x, and ∠B and ∠E be y ∠D=x-67=y/2 y=2x-134 2x+2(2x-134)+x-67=540 2x+4x+x+268-67=540 6x=540-268+67 x=339 y=678-134=544 ∠A and ∠C =339,∠D=272,∠B and ∠E=544 7 let the height of the plant one year ago be x x(1+24%)=186 x=6x25 =150 a 150cm b [186(1-12%)]cm=163.88cm
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