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Question

Please help with below question. Thank you.

At a gift shop, the number of $2 gift packs, $5 gift packs and $10 gift packs were in the ratio of

16 : 9 : 7.     1/8 of the $2 gift packs and 34 of the $5 gift packs were sold.  The remaining gift packs were worth $1975.  How many of the $10 gift packs were there?

 

Answer

At first

Qty:

$2 -> 16u

$5 -> 9u

$10 -> 7u

1/8 of $2-pack, and 34 of $5-pack were sold

Qty:

$2 -> 14u

$5 -> 9u – 34

$10 -> 7u

Pack Value:

$2 -> 14u x 2 = 28u

$5 -> (9u – 34) x 5 = 45u – 170

$10 -> 7u x 10 = 70u

28u + 45u – 170 + 70u = 1975

143u = 2145

1u = 15

There were 7 x 15 = 105 $10 gift packs

 

1 Reply 2 Likes

Thank you for your solutions, BigDevil, Ender and SAHMom.
Really appreciate it.

1 Reply 1 Like

Glad to help. 🙂

 

0 Replies 0 Likes

 

Hi,

We may use a table to list it.

 

  $2  $5   $10   Total  
Before 16u  9u 7u  
After 14u 9u – 34     7u  
Each $2 $5 $10  
Amount 28u 45-170 70u 143u-170

 

143u – 170 = 1975
143u = 1975 + 170
143u = 2145
1u = 15

7u = 7 × 15 = 105 packs

I found that using table, some kids are able to understand the question better. Not all kids understand the model drawing.

However, I do not understand why primary teacher use arrow instead of equal sign.

143u — > 1975 + 170

Then in secondary school, the teachers taught the student to use equal sign in equation.

143u = 1975 + 179

Why can’t they do in a consistent way?

2 Replies 2 Likes

Thank you for your working, Khong Pek Mao.

0 Replies 0 Likes

When I first started ‘re-learning’ primary school math in order to coach my son. I am also baffle with the arrows in place of ‘=’. 

Now have gotten use to seeing it, even though I don’t use it in my solution.

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16u of $2 gift pack. If 1/8 are sold, 7/8 are left which is, => 14u

34 of $5 pack is worth 34 X 5 = $170
Left over value of $5 pack = 9u($5) -170

Total leftover value is,
14u ($2) + 9u ($5) – $170 + 7u($10) = $1975
28u + 45u + 70u – 170 = 1975
143u = 2145
u = 15

$10 pack = 7u = 105 packs. ##

0 Replies 2 Likes

Try table for summarising info (view landscape):

                          $2-gift                   $5-gift          $10-gift        Total

add back “non-units”               34x$5=$170                       $1975+$170=$2145

units “left”           16u-2u                 9u                    7u

1 set                     14x$2                  9x$5              7x$10                   =$143

$2145/$143 = 15 sets

no. of $10-gift = 7 X 15 =105 packs#

0 Replies 2 Likes