我有幾題唔識做幫幫手!唔該 ! (Maths)

2009-07-20 6:38 pm

1)The depth of water in a pool is d cm. If the depth of water decreases by 35%and become 1.82m, find the vaule of d.

2)The following is the expenditure of a family in a certain month: $1800on transportion, $2500 on food, $1700 on others. Express the expenditure on transportionas a % of that month's expenditure.

3)Mary got 50 marks in the first Chinese dictation. If her mark in the second Chinese dictation increased by 20%,and her mark in her third Chinese dictation was20% more than the second dictation, find her mark of the third Chinese dictation.

4)The electricity bill of Mary's family in August was $560. If in the next two consecutive months, the use of electricity is less thaan each previous month by 15%, find the electricity bill of Mary's family in October. (Give the answer correct to the nearest integer)

回答 (1)

Hse

2009-07-20 6:58 pm

✔ 最佳答案

1) d should be larger than 1.82m
so, d x 65% = 1.82, answer is 2.8m= 280cm

2) 1800/(1800+2500+1700) x 100% =30%

3) first, second mark should be 50 x (1+20%) = 60
and the third one, 60 x (1+20%) = 72

4) Sept bill: 560- (560x15%)=476 or 560 x 85% = 476
Oct bill: 476-(476x15%)=404.6=405 or 476 x 85% = 404.6

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我有幾題唔識做 幫幫手!唔該 ! (Maths)

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我有幾題唔識做幫幫手!唔該 ! (Maths)