? asked in 科學及數學數學 · 1 decade ago

HOMEWORK....HELP2方程

1.Bobby saves a fixed amount of money every day.He finds that the price of a model is $70 more than his savings in 5 days or $10 more than his saving in 9 days.How much does he save each day?

2.A sum of $120 is divided between two sisters.The eldae sister spends 1/5 of the amount recived while the younger sister spends 1/6 of the amount recived.If the eldersister spends$13 more than the younger sister,how much does each of them recived?

D式可唔可以詳細D...

3 Answers

Rating
  • Amby
    Lv 6
    1 decade ago
    Favorite Answer

    1.Bobby saves a fixed amount of money every day.He finds that the price of a model is $70 more than his savings in 5 days or $10 more than his saving in 9 days.How much does he save each day?

    let x be the money he saves per day

    5x+70=9x+10

    4x=60

    x=15

    so he saves $15 per day

    2.A sum of $120 is divided between two sisters.The eldae sister spends 1/5 of the amount recived while the younger sister spends 1/6 of the amount recived.If the eldersister spends$13 more than the younger sister,how much does each of them recived?

    let elder sister recieved $x,then young sister recieved $(120-x)

    x*(1/5)=(120-x)*(1/6)+13

    x/5=(120-x)/6+78/6

    x/5=(120-x+78)/6

    x/5=(198-x)/6

    5(198-x)=6x

    990-5x=6x

    990=11x

    x=90

    so elder sister recieved $90 and younger sister recieved $30

  • 1 decade ago

    (1)

    let x be the money he saves per day

    5x+70=9x+10

    4x=60

    x=15

    so he saves $15 per day.

    (2)

    let elder sister recieved $x,then young sister recieved $(120-x)

    x*(1/5)=(120-x)*(1/6)+13

    x/5=(120-x)/6+78/6

    x/5=(120-x+78)/6

    x/5=(198-x)/6

    5(198-x)=6x

    990-5x=6x

    990=11x

    x=90

    so elder sister recieved $90 and younger sister recieved $30.

    Source(s): myself
  • Anonymous
    1 decade ago

    1. Let $x be the fixed amount of money every day,

    70+5x = 10+9x

    4x = 60

    x = 15

    so the amount is $60

    2006-10-19 20:06:11 補充:

    $15 is corect.

Still have questions? Get your answers by asking now.