中一方程計算急...

2012-12-12 7:29 am

The amount Tim spends on entertainment each month is 2 over 3of that of his sister, Mary.

A)If Tim spend $150 more and Mary spend $150 less each month , then Mary's expenditure becomes 2 over 3 of Tim's.How much does each spend on entertainment each month?

B) Tim and Mary want to buy a bicycle and a TV game. The money needed is $140 less than twice of the amount they have planned for entertainment each month. If the price of the bicycle is 4 over 13 of that of the TV game, what is the price of the TV game

請逐步計+ some 解釋 THX!!!

回答 (1)

[匿名]

2012-12-12 8:06 am

✔ 最佳答案

A)
Let $m be the amount that Mary spends on entertainment.
Then, the amount that Tim spends on entertainment = $2m/3

If Tim spends $150 more, he spends $[(2m/3) + 150].
If Mary spends $150 less, she spends $(m - 150)

Mary's expenditure = (2/3) of Tim's expenditure
(m - 150) = (2/3)[(2m/3) + 150]
m - 150 = (4m/9) + 100
(5m/9) = 250
m = 450
2m/3 = 300

The amount that Mary spends on entertainment = $450
The amount that Tim spendson entertainment = $300

B)
Let $t be the price of TV game.
Then, the price of the bicycle = $4t/13

(The money needed for bicycle and TV) = 2 x (the amount for their entertainment)- 140
t + (4t/13) = 2 x (450 + 300) - 140
17t/13 = 1360
t = 1040

The price of the TV game = $1040

參考: Adam

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中一方程計算 急...

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中一方程計算急...