Algebra Homework Help?

Hi, I was wondering if i could get help on these homework problems. Please provide the steps on answers.

1: Some 10% salt solution is mixed with some 30% salt solution to make 20 L of 16% salt solution. How much of each was mixed to make the solution.

2: A chemist has 500 L of a 15% acid solution. How much pure acid should be added to make a 20% acid solution.

3: How many liters of a 14% alcohol solution must be mixed with 20 L of a 50% acid solution to get a 20% alcohol solution.

4: John skates across a frozen lake at 10 MPH and returns at 5 MPH. If his skating time is one hour, how wide is the lake?

5: Amanda can row 32 miles downstream in 8 hours but it takes her 6 hours to row 12 miles upstream. Find the rate she rows in still water and the rate of the current.

6: Two planes leave the JFK airport at the same time. Plane A travels east and plane B travels west. The average speed of plane A is 60 km per hour faster than the speed of plane B. After 2.5 hours of flying time, the planes are 4150 km apart. What are the speeds of the planes?

7: Los Angeles and San Diego are 210 miles apart. A truck traveled from LA toward SD at the rate of 48 MPH. Another truck traveled from SD toward LA at the rate of 42 MPH. Both trucks started at the same time. How long will it take for them to meet each other.

8: Jordan can clean the cafeteria in 25 minutes. Ida can clean the cafeteria in 33 minutes. if they work together, approximately how long will it take them to clean the cafeteria.

9: The inlet pipe of an oil truck can fill in 4 hours. The outlet pipe can empty the tank in 6 hours. Find how long it takes to empty a full tank if both pipes are open.

10: Tina and Jane can paint an apartment in 5 hours working together. If Tina can do the same job alone in 7 hours, how long will it take Jane to finish alone?

11: How many pounds of chocolate worth $1.20 a pound must be mixed with 10 pounds of chocolate worth 90 cents a pound to produce a mixture worth $1.00 a pound?

12: The owner of a food store wants to mix cashews selling at $8.00 per kg and pecans selling at $6.00 per kg. How many kilograms of each should be mixed to get 12 kg of nuts worth $7.50 per kg?

Sorry for the lengthy post, this was originally a test but it was so difficult that no one finished in the period. I feel like I did something wrong for all the questions and I want to get help step by step. I know this will probably waste a lot of your time, but please help. You"ll be helping a 7th grader who's failing algebra. :)

2 Answers

  • 7 years ago
    Best Answer

    Sorry, I've just looked down the list and calculated two chosen at random in my head, without batting an eyelid. I left school 30years ago and wouldn't say I am anything remotely 'special'. I'm honestly shocked if none of your fellow pupils completed these in your period, (let alone in about 20 seconds their heads!).

    Please raise the matter with your teacher or Principle as something's seriously amiss. I've no doubt most/all kids aged 10 or 11 taught in the Far East or Asian sub-continent would find these awfully, awfully, easy!!

    Sincere apologies if this sounds a bit harsh...but these questions are about as basic as they come and your teachers are getting paid to educate you! :/

  • 7 years ago

    I'm not goin to do all of them, because frankly, I'm too lazy. Ou should do your own homework. Ask te teacher for help, I'm sure they'd gladly give it to you. And try to go to te books website. Maybe they can give you some of the answers or help you.

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