請幫忙列式計算以下數學題

candy7_fong

2011-01-12 9:28 pm

請幫忙列式計算以下數學題:
1) Shirley has tree types of coins: $1-coins , $2-coins. The number of $5-coins is more than the number of $1-coins by 3, while the number of $2-coins is 8 more than twice the number of $5-coins If shirley has 97 coins altogether, find the value of the coins.2) The difference of two numbers is 8 , and their sim is 88. Find the value of the larger number.3) John's saving is $300 more than his sister's . After giving $450 from his savings to his sister John's savings become 2/5 (5份2) of his sister's . How much savings do they have toghether?

回答 (1)

myisland8132

2011-01-12 10:07 pm

✔ 最佳答案

1 Let Shirley has x $1-coins. Then she has (x+3) $5-coins and 2(x+3)+8 or ( 2x+14) $2-coins

So, x+x+3+2x+14=97

4x=80

x=20

The value of the coin

=x+5(x+3)+2(2x+14)

=20+5(23)+2(54)

=243

2 Let the numbers are x and x+8. Then x+x+8=88 => x=40

The value of the larger number is 48

3 Let John's sister has $x originally. Then John's has $ (x+300)

(x+300)-450=(2/5)(x+450)

x-150=0.4x+180

x=550

They have 550+550+300=1400 savings altogether.

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