# Thread: Problem set: inequalities, ratios, basic algebra

1. ## Problem set: inequalities, ratios, basic algebra

1. Write the following inequality as interval notation 2 < x ≤ 5
2. The ratio of two numbers is 7:2 The two numbers add up to 90 find the two numbers.
3. Twenty less than a number is 56
4. i am thinking of a number such that 6 less than the product of 7 and this number is 85
5. A classroom contained an equal of number of boys and girls. Eight girls left to play hockey, leaving twice as many boys as girls in the classroom. what was the original number of students present.

2. Originally Posted by Bijou
that's our line!

i'm sorry, this is not a homework or answer service. we don't just give out answers. we help you to get to them yourself. please show your work and explain where you got stuck or what you don't understand

this smells like you want us to do your homework, which is not good, and against MHF policy.

3. ok can you help me

4. Originally Posted by Bijou
ok can you help me
um...you didn't do anything.

show your work for each problem and explain where you are stuck or what you don't understand...

5. im i dont understand any of them so can we start at number 1

6. Originally Posted by Bijou
im i dont understand any of them so can we start at number 1
In that case, doing them for you is not going to help you understand them. You need to go back to your class notes of textbook and review the material. Then you need to arrange one-on-one help from your teacher or some other love instructor.

Here is #1, for what it's worth: (2, 5].

7. for #2, the question gives you two pieces of information:
(1) x/y = 7/2
(2) x +y = 90
can you solve them now using simultaneous equations?

for #3,
x - 20 = 56 , solve for x

for #4,
7x - 6 = 85 , solve for x

do you think you could do #5 by yourself now? It seems as though you are having trouble understanding what the actual questions are asking, you should definitely ask your teacher for some help.

8. thanks but i really dont get 5 i got 16 as a answer which is wrong im stuck?

9. can you explain question #2 much better thanks

10. for #2..
let x and y be the two numbers you are looking for.
when it says the ratio of the two number is 7:2, it means x:y = 7:2.. this is the same as saying x/y = 7/2
if you multiply both sides of that equation by y,
you get x = (7y)/2

you are also given x + y = 90
now you sub in x = (7y)/2 into x + y = 90 and see what you get

in #5, you are also given two pieces of information.
if we let g=# of girls, b=# of boys, we have

initially, g=b and when 8 girls leave, g-8 = b/2
Can you use these pieces of information to work it out? Remember you are trying to find the original number of students present (boys + girls)

11. Originally Posted by Bijou
thanks but i really dont get 5 i got 16 as a answer which is wrong im stuck?
You have calculated the number of boys (which is also the same as the number of girls) .... (One of the reasons why you should always write down the definition of any pronumeral you use at the very start of your solution).

12. for #5 i got 4 as a answer 16 -8=8 then 8 divided by 2 = 4 right or wrong?

13. Originally Posted by Bijou
for #5 i got 4 as a answer 16 -8=8 then 8 divided by 2 = 4 right or wrong?
You got 4 as an answer? Does that even make sense to you?

The question asked "What was the original number of students?" and you were told "8 girls left".

If there were only 4 students originally, how could 8 girls have left?

THINK!