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By: 2000123 (offline)  Saturday, May 26 2012 @ 07:57 AM CDT (Read 1022 times)  
2000123

There are some coins in a box.
2/3 of them are 10-cent coins,1/6 of them are 20-cent coins and there is an equal number of 50-cent coins and 1 dollar coins.
The total value of the coins is $81.
Find the value of all the 20-cent coins.Express your answers in $.

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By: echeewh (offline)  Saturday, May 26 2012 @ 07:23 PM CDT  
echeewh

Hi there,

Following pls find the worked solution ..

<< Notes: 28/5 - corrected worked solution (see ** ) for the final result. Interpreted question wrongly earlier, in which the fraction or proportion of the different denominations of coins represents the quantity (qty) or number, rather than amount of money / value. >>

10cts: 2/3 = 4/6
20cts: 1/6
Hence, number of 50cts + $1 coins = 1/6.
Given that number of 50cts and $1 coins are equal, we now have ...
50cts: 1/6 ÷ 2 = 1/12
$1: 1/12

So now we can translate the above proportions into units (u),
10cts: 4/6 = 8/12 --> 8u
20cts: 1/6 = 2/12 --> 2u
50cts: 1/12 --> 1u
$1: 1/12 --> 1u

**<using Number x Value method>, we have...

Total value of coins:
(8u x 0.10) + (2u x 0.20) + (1u x 0.50) + (1u x 1.00)

Given that total value of all these coins is $81, we have ...

0.8u + 0.4u + 0.5u + 1u --> 81
2.7u --> 81
1u --> 81 ÷ 2.7 = 30

Number of 20cts = 2u --> 2 x 30 = 60
Value of these 20cts coins = 60 x 0.20 = $12

=====================================

Trust the above helps.

Cheers,
Edward

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By: 2000123 (offline)  Saturday, May 26 2012 @ 10:28 PM CDT  
2000123

Thanks for your solution.It helps.

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