coin problem
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coin problem
Hi
Please can anyone help me with this problem. i think it is a ratio problem which for the life of me i cannot work out.
A cash box contains some coins to the value of £5.25.
There are twice as many 5p coins as 2p coins, and twice as many 2p coins as 1p coins.
This means there are:
1. how many 5p coins
2. how many 2p coins
3. how many 1p coins
Please help.
Please can anyone help me with this problem. i think it is a ratio problem which for the life of me i cannot work out.
A cash box contains some coins to the value of £5.25.
There are twice as many 5p coins as 2p coins, and twice as many 2p coins as 1p coins.
This means there are:
1. how many 5p coins
2. how many 2p coins
3. how many 1p coins
Please help.
Re: Maths
Think how much money is made from one set of the coins.
1p + 4p (2, 2p - 2 x no. of 1p) + 20p (4, 5p - 2 x no. of 2p coins) = 25p
How many 25p in £5.25? 21
So 21 1p coins is 21p
42 2p coins is 84p and
84 5p coins is 420p
Check
21 + 84 + 420 = 525
1p + 4p (2, 2p - 2 x no. of 1p) + 20p (4, 5p - 2 x no. of 2p coins) = 25p
How many 25p in £5.25? 21
So 21 1p coins is 21p
42 2p coins is 84p and
84 5p coins is 420p
Check
21 + 84 + 420 = 525
Re: Maths
I taught ratio by drawing beads.
I would start with that.
green bead costs 1p
red bead costs 2p
blue bead costs 5p
For every green bead there are two red beads.
GRR
For every red bead there are two blue beads, so your bracelet has this pattern.
GRRBBBB
1+2+2+5+5+5+5
The cost of these beads is: 1p + 4p + 20p = 25p
How many sets of GRRBBBB can you buy for £5.25. The answer is 21 (525/25)
So your bracelet has
21 G
42 R and
84 B.
I would start with that.
green bead costs 1p
red bead costs 2p
blue bead costs 5p
For every green bead there are two red beads.
GRR
For every red bead there are two blue beads, so your bracelet has this pattern.
GRRBBBB
1+2+2+5+5+5+5
The cost of these beads is: 1p + 4p + 20p = 25p
How many sets of GRRBBBB can you buy for £5.25. The answer is 21 (525/25)
So your bracelet has
21 G
42 R and
84 B.
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Re: Maths
*If there are two 5p coins then there is one 2p coin (the ratio is 2:1)kentlady wrote:Hi
Please can anyone help me with this problem. i think it is a ratio problem which for the life of me i cannot work out.
A cash box contains some coins to the value of £5.25.
There are twice as many 5p coins as 2p coins, and twice as many 2p coins as 1p coins.
This means there are:
1. how many 5p coins
2. how many 2p coins
3. how many 1p coins
Please help.
*If there are two 2p coins then there is one 1p coin (the ratio is 2:1)
Which can also be rewritten as:
*If there are four 5p coins, then there are two 2p coins and one 1p coin (the ratio is 4:2:1, we are taking all the coins into account to form a ratio)
*If we write this in the form of an equation it will be like this:
4(5p) + 2(2p) + 1(1p) = 20p + 4p + 1p = 25p
*Now that you know that this gives you 25p you have to do:
5.25/0.25 = 21
*This means the following equation occurs 21 times:
4(5p) + 2(2p) + 1(1p) = 20p + 4p + 1p = 25p
*Therefore there are:
21 x 4(5p) = 84 x 5p coins
21 x 2(2p) = 42 x 2p coins
21 x 1(1p) = 21 x 1p coins
(84 x 5) + (42 x 2) + (21 x 2) = 525p
Last edited by Rainbow Petals on Thu Aug 29, 2013 11:28 am, edited 1 time in total.