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 By: Jlen (offline)  Friday, July 26 2013 @ 09:50 PM CDT (Read 785 times)
Jlen

Hi all,

Pls help me with the below question.

Siting had some pens.2/5 of them were red and the rest were blue.
She sold 5/8 of the red pens and 2/3 of the blue pens.She had 70 pens
left.How many pens did Siting have at first?

Ans: 200

Thanks for help.

Regards,
Jlen

Newbie

Registered: 05/05/13
Posts: 10

 By: echeewh (offline)  Saturday, July 27 2013 @ 07:33 PM CDT
echeewh

Hello <Jlen>,

Following is my worked solution:

<Before>

R : B
2 : 3

<Process>

R: (5/8) sold; (3/8) remained.
(3/8) × 2u = (3/4)u

B: (2/3) sold; (1/3) remained.
(1/3) × 3u = 1u

<After>

R : B
(3/4) : 1

Multiply this 4x:

3 : 4

Likewise, multiply <before> ratio 4x. {since these units are derived from it}

<Before>

R : B
8 : 12

Given there were 70 pens left, we have ...
7u --> 70
1u --> 10

Pens (R+B ) (at first) = 8u + 12u = 20u
20u --> 20 × 10 = 200

=======

Trust this helps.

Do let me know again if there's further clarification.

Cheers,
Edward

Active Member

Registered: 04/21/11
Posts: 627

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