Help maths question!?!??!?! A.S.A.P!!?

Question

If I don't do this, I am so dead at school!! URGENT!!
A few questions if you don't mind?
1) Jill and Penny have 217 stamps. If penny gives 12 of her stamps to Jill, Jill will have 2 1/2 times as many stamps as Penny. How many stamps has Penny at first?

2) The total cost of a book and a dictionary is $56. The total cost of 8 such books and 5 such dictionaries is $376. Ali pays 3 book and 2 dictionaries with 'TWO' $100 notes. (a) What is the cost of 3 book and 2 dictionaries? (b) How much change will he receive?

3) Ali, Ben & Chen had 98 pencils altogether. After Ali gave away 5 pencils, Ben doubled his pencils and Chen received 3 more pencils, the ratio of the pencils of Ali to Ben to Chen became 1:4:5 respectively. How many pencils did each of them have at first?

I know that I am suppose to find it on my own. My maths isn't that great so I would be glad if you would help and try to teach me your method. Thanks!

Answer 1

1) Let the no. of stamps Jill has at first be x.
So Penny has 217-x stamps at first.

217-x-12 = 2.5 (x+12)
205-x = 2.5x+30
175x = 3.5x
x = 50


So Penny has 217-50 = 167 stamps at first.

2) Total cost of 5 books and 5 dictionaries
= $56 X 5 = $280
Cost of 3 books = $376 - $280 = $96
Cost of 1 book = $96 / 3 = $32
Cost of 1 dictionary = $56 - $32 = $24

a) Cost of 3 books and 2 dictionaries
= $96 + 2 X $24 = $144
b) Change he receives
= $200 - $144 = $56

3) Let the no. of pencils Ali has at first be x,
the no. of pencils Ben has at first be y,
and the no. of pencils Chen has at first be z.

x + y + z = 98

x-5 : 2y : z+3 = 1 : 4 : 5

This means that:

5(x-5) = z+3
z = 5x-25-3 = 5x-28

and

4(x-5) = 2y
y = 2x-10

Therefore,
x + 2x-10 + 5x-28 = 98
8x = 136
x = 17

y = 2x-10 = 24

z = 5x-28 = 57

Answer 2

If penny had 167 stamps to start out of 217 that would leave jill with 50 stamps at first. Even if you minus and add 12 twice jill wouldn't have 2 1/2 times more stamps than penny. I'm pretty sure thats wrong. Not that i'm fantastic at math, either. Please tell me if you find out which is the answer. What age group is this for?
1.) 217 divided by 3.5 = 62 [ you divide by 3.5 because it has the equal ratio to 2 1/2 times penny's amount, plus hers.] 62 divided by 2 = 31 [ this tells how much the 1/2 is worth] 31- 12 = 19 [ this plus ] 19+124 or (62x2)= 124 [is how much Jill had before penny gave her the 12 stamps] 62 + 12 = 74 stamps penny had at first.

Answer 3

for question # 2:
a) The cost of 3 books is $96 and the cost of 2 dictionaries is $48. The total cost is $144
b) He will receive $56 as change

Answer 4

Dear, these are simple enough for anyone to understand. You can do these. Have you even tried solving? If it is so urgent as you say it is, you will sit down, think on these questions, and work hard. You'll get it soon enough, guaranteed.

You might say that your math isn't that great so this would be a perfect opportunity for you to improve it!

Happy learning!