有幾題數學唔識做,,,,,,help－vbd391t的部落格

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有幾題數學唔識做,,,,,,help

發問:

1. If the two adjacent sides of a square measure x cm and (2x - 3) cm respectively, find the perimeter of the square.2. Ann ahd $100. She used part of her money to buy 7 ceramic cats, in which 3 of them are more expensive than the rest by $3. If she had $7 left, how much do the two types of ceramic cat cost?3.... 顯示更多 1. If the two adjacent sides of a square measure x cm and (2x - 3) cm respectively, find the perimeter of the square. 2. Ann ahd $100. She used part of her money to buy 7 ceramic cats, in which 3 of them are more expensive than the rest by $3. If she had $7 left, how much do the two types of ceramic cat cost? 3. The coat of tea A is $30 per kg, the coat of tea B is $20 per kg,If w kg of tea A and (w+1) kg of tea B are mixed together, and the coat of the mixed tea is $24 per kg. Find w. 4. Ann had a bag of glass beads. She used half of the beads to make a necklace. She and her sister then use 1/6 and 1/7 of the beads respectively to make twp bracelets. If there are 16 glass beads left, find the original number of glass geads. 5.The height of a small tree is h cm. One month later, its height increases by 28% to 44.8 cm, fing the value of h. 6. The depth of water in a pool is d cm. If the depth of water decreases by 35% and becomes 1.82m, find the value of d. 7. The following is the expenditure of a family in a certain month: $1 800 on transportation, $2500 on food, $1700 on others, Express the expenditure on transportation as a percentage of that month's expenditure. 8. Mary got 50 marks in the first Chinese dictation. If her mark in the second Chinese dictation increased by 20%, and her mark in the third Chinese dictation was 20% more than the second dictation, find her ark of the third Chinese dictation. 9. The electricity bill of Mary's family in Augest was $560. If in the next two consecutive months, the use of electricity is less than each previous month by 15%, find the electricity bill of Mary's family in October. 更新: 勞煩列式計算

最佳解答:

1.A square has 4 equal sides. x= 2x-3 x=3 the perimeter of the square= 3*4=12cm 2. Ann ahd $100. She used part of her money to buy 7 ceramic cats, in which 3 of them are more expensive than the rest by $3. If she had $7 left, how much do the two types of ceramic cat cost? Let the two types of ceramic cat be $x. the cost of 3 more expensive cats + the cost of 4 cheaper one = $(100-7) 3x + 4(x-3)=93 7x-12=93 x = 105/7 =15 The cost ofmore expensive type of cat=$15 when the the cost of the cheaper one=$12 3. The coat of tea A is $30 per kg, the coat of tea B is $20 per kg,If w kg of tea A and (w+1) kg of tea B are mixed together, and the coat of the mixed tea is $24 per kg. Find w. 30w+20(w+1)=24 50w =4 w = 0.08 4. Ann had a bag of glass beads. She used half of the beads to make a necklace. She and her sister then use 1/6 and 1/7 of the beads respectively to make twp bracelets. If there are 16 glass beads left, find the original number of glass geads. Let the original number of glass beads be x. 1/2x - 1/2x *1/6 - 1/2x *1/7 =16 1/2x(1- 1/6 - 1/7) =16 x =32/(29/42) (Does this question have some critical typing mistakes?) 5.The height of a small tree is h cm. One month later, its height increases by 28% to 44.8 cm, fing the value of h. h*(1+28%)=44.8 h = 44.8/1.28=35 6. The depth of water in a pool is d cm. If the depth of water decreases by 35% and becomes 1.82m, find the value of d. d*(1-35%)=1.82 d =1.82/0.65=2.8 7. 1800/(1800+2500+1700) *100% = 30% 8. 50(1+20%)(1+20%)=72 marks 9. 560(1-15%)(1-15%)=$404.6