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137 simultaneous equation

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137 simultaneous equation

by phoenix9801 » Sat Jul 10, 2010 11:14 pm
Hi, can someone please help to explain by step-by-step instructions (in detail) in the most simplest way and clear to understand. Would Greatly appreciate it.


At a bakery, all donuts are priced equally and all bagels are priced equally. What is the total price of 5 donuts and 3 bagels at the bakery?

(1) At the bakery, the total price of 10 donuts and 6 bagels is $12.90

(2) At the bakery, the price of a fount is $0.15 less than the price of a bagel.
Last edited by phoenix9801 on Mon Jul 12, 2010 1:48 pm, edited 1 time in total.
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Source: — Data Sufficiency |
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by albatross86 » Sat Jul 10, 2010 11:25 pm
Let price of each donut be D and of each bagel be B.
What is 5D + 3B?

1. 10D + 6B = 12.90$

This is an important takeaway for DS. Whenever you have an equation like this which is actually just a multiple of our required solution, it is sufficient, and though we have two variables, we can isolate our target value.

i.e. Divide the above equation by 2:

5D + 3B = 6.45@ ...Ans

SUFFICIENT

2. D = B - 0.15$

This won't be sufficient to find each value or to obtain 5D + 3B

INSUFFICIENT

Pick A.
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by phoenix9801 » Mon Jul 12, 2010 1:47 pm
albatross86 wrote:Let price of each donut be D and of each bagel be B.
What is 5D + 3B?

1. 10D + 6B = 12.90$

This is an important takeaway for DS. Whenever you have an equation like this which is actually just a multiple of our required solution, it is sufficient, and though we have two variables, we can isolate our target value.

i.e. Divide the above equation by 2:

5D + 3B = 6.45@ ...Ans

SUFFICIENT

2. D = B - 0.15$

This won't be sufficient to find each value or to obtain 5D + 3B

INSUFFICIENT

Pick A.

Thanks for the help....

I would know if you can further explain what you mean by this " Whenever you have an equation like this which is actually just a multiple of our required solution, it is sufficient"?????????????
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