幫幫手數學

某人上月use係食物的支出是$1500,use係服裝的是$2500.這月她在食物和服裝的支出分別減少25%和15%.

(b)她的總支出的百分數增減是多少 ?

4 個解答

評分
  • 1 十年前
    最愛解答

    new expense = 1500 * (1-0.25) + 2500 * (100.15)

    =1500*0.75+2500*0.85

    =1125+2125

    =3250

    b. (3250 - 4000)/4000 = -0.1875

    drop 18.75%

  • 1 十年前

    percentage change :

    ( 1500*(1-25%) + 2500*(1-15%) - (1500+2500) ) / (1500+2500) * 100%

    = -750/4000 * 100%

    = -18.75%

    therefore , there is a percentage decrease for 18.75% in her expenses.

  • 1 十年前

    本月的食物支出=1500X(1-25%)

    =$1125

    本月的食物支出=2500X(1-15%)

    =$2125

    因為她的總支出的百分數增減=(新值-舊值)/舊值X100%

    =((1125+2125)-(1500+2500))/(1500+2500)X100%

    = -18.75%

    所以她的總支出的百分數減少18.75%

  • 1 十年前

    上月總支出=$1500+$2500

    =$4000

    今月食物支出= $1500(1-25%)

    =$1125

    服裝支出=$2500(1-15%)

    =$2125

    今月總支出=$1125+$2125

    =$3250

    總支出的百分數增減= $(3250-4000)/$4000 * 100%

    = -750/4000 *100%

    = -18.75%

    總支出減了18.75%

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