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## Comment on

Simple Interest and Compound Interest## in this above question how

## c = the # of times the

c = the # of times the interest is compounded each year.

The question tells us that interest is compounded every month.

Since there are 12 months in a year, we know that the interest is compounded 12 times each year

## Could you possibly give a

## You bet.

You bet.

Here's the question:

Pat invested a total of $3000 dollars. Part of the money was invested in a money market account that paid 10% SIMPLE annual interest, and the remainder of the money was invested in a fund that paid 8% SIMPLE annual interest. If the TOTAL interest earned at the end of the first year from these investments was $256, how much did Pat invest at 10% and how much at 8%?

Let x = amount invested at 10% interest

So, 3000-x = amount invested at 8% interest (since the two investments, when combined, must add to $3000)

So, the annual interest for the 10% investment = 0.1x

The annual interest for the 8% investment = 0.08(3000 - x)

The TOTAL interest earned is $256, so...

We can write: 0.1x + 0.08(3000 - x) = 256

Expand: 0.1x + 240 - 0.08x = 256

Simplify left side: 0.02x + 240 = 256

Subtract 240 from both sides: 0.02x = 16

Solve: x = 800

So, $800 was invested at 10% and the remaining $2200 was invested at 8%

## Thank you!!

## Shouldn't the formula be 1.1x

## The question focuses solely

The question focuses solely on the total INTEREST that accumulates.

Your equation focuses on the total value of the investments (i.e., it represents the interest PLUS the initial investment.

For example, 0.1x represents the INTEREST that accumulates on x dollars at 10% interest.

Conversely, 1.1x represents the TOTAL VALUE of the investment of x dollars with 10% interest added to it.

Does that help?

## Yes, thank you. I really

## Hi, How did you solve

## Hi Shukameli,

Hi Shukameli,

In the future, please transcribe the question.

The question is as follows: Kathleen's weekly salary was increased by 8 percent to $712.80. What was her weekly salary before the increase?

Let x = Kathleen's weekly salary BEFORE the increase

8% = 0.08

So, 8% of x = 0.08x

So, if we take her weekly salary BEFORE the increase (x) and increase it by 8%, we are adding an additional 0.08x to her salary to get a new salary of $712.80

We can write: x + 0.08x = $712.80

Simplify: 1.08x = $712.80

Solve: x = $712.80/1.08 = $660

NOTE: in general, if we want to increase a value by 8%, we just multiply the value by 1.08.

Likewise, if we want to increase a value by 13%, we multiply the value by 1.13.

If we want to increase a value by 38%, we multiply the value by 1.38.

and so on.

Does that help?

Cheers,

Brent

## https://gre.myprepclub.com/forum

This questions doesn't have anything to do with this section but i just wanted to know what section to find these question types.

Thank You

## Question link: https:/

Question link: https://gre.myprepclub.com/forum/the-number-0-is-between-the-two-nonzero...

As with many math questions, this question tests two different concepts:

1) Number line

2) Rules regarding products of positive/negative numbers

Given this, I would place this question under the following video: https://www.greenlighttestprep.com/module/gre-arithmetic/video/1059

## https://gre.myprepclub.com/forum

What section would I find these types if question and lessons?

Thank You

## Question link: https:/

Question link: https://gre.myprepclub.com/forum/steve-s-property-tax-is-140-less-than-p...

This is definitely at percent question.

It would fit as a "percent increase/decrease" question here: https://www.greenlighttestprep.com/module/gre-arithmetic/video/1083

It would also fit as a regular percent question here: https://www.greenlighttestprep.com/module/gre-arithmetic/video/1078

I should also mention, that in my solution (https://gre.myprepclub.com/forum/steve-s-property-tax-is-140-less-than-p...), I use a nice fraction property to quickly convert $140/$2000+ into an approximate percent.

That fraction property occurs here: https://www.greenlighttestprep.com/module/gre-arithmetic/video/1067

Cheers,

Brent

## https://gre.myprepclub.com/forum

Shouldnt the answer to this question be D? Since we can't tell the original price amount?

## No, the answer will always be

No, the answer will always be B.

Here's my full solution: https://gre.myprepclub.com/forum/john-buys-a-shirt-at-80-of-its-tagged-p...

## Hey Brent a non gre type

https://gre.myprepclub.com/forum/john-buys-a-shirt-at-80-of-its-tagged-price-18135.html#p56152

What u wrote:

Buying a shirt at 80% of the tagged price represents a 20% discount.

Buying a shirt at 70% of the tagged price represents a 30% discount.

Paying $80 for a $100 shirt means a discount of $20

Paying $70 for a $100 shirt means a discount of $30

Total discount = $50

Total amount we would have paid WITHOUT the discount = $200

So, the total discount of $50, represents a discount of 25% (since $50/$200 = 25%)

than due to this

So in the market if i buy for example a toy at 20% discount i pay 80% of value and another for 70% of value at 30% off

means i get 50% percent points of discount on total. we get 50% as they have same base i.e. price

Please bear with me than if total bill on no discount was 200 so 50/200 is 25% discount on total it doesnt mean that i recived a discount of 50% but acutally 25%

if thats true my mind is blown on how they do pricing.....can u tell me if what i say is correcct?

_________________

## Question link: https://gre

Question link: https://gre.myprepclub.com/forum/john-buys-a-shirt-at-80-of-its-tagged-p...

"So in the market if i buy for example a toy at 20% discount i pay 80% of value and another for 70% of value at 30% off means i get 50% percent points of discount on total. we get 50% as they have same base i.e. price"

The above statement is not correct. In my example, the total discount equals $50, and since I was supposed to pay a total of $200 for the two shirts, the $50 discount represents a saving of 25%.

"Please bear with me than if total bill on no discount was 200 so 50/200 is 25% discount on total it doesnt mean that i recived a discount of 50% but actually 25%)

Not quite. All we can say is that, if the original price of each shirt was $100, then after the two discounts, you would get a total discount of 50 DOLLARS, which represents a total discount of 25 PERCENT.

## Hi Brent,

I came over this type of question where the principle is not given. Can you help me to solve this?

Maggie bought a 1-year certificate of deposit and annual interest earned on the deposits if 6 percent compounded semi annually. What was the amount invested, if interest earned on the certificate at maturity is $60.9?

## r = 0.06

r = 0.06

c = 2

n = 1

and we'll let P = the principle

Final value after 1 year = P(1 + 0.06/2)^(1 x 2) = P(1.03)^2

Note: this is new VALUE of the investment, including the principle.

We just want just the interest.

So: INTEREST = P(1.03)^2 - P

Factor to get: interest = P[(1.03)^2 - 1]

Evaluate the power: interest = P[1.0609 - 1]

Simplify: interest = P[0.0609]

Substitute given value: $60.90 = 0.0609P

Solve: P = $60.90/0.0609

P = $1,000

## Hi Brent,

Thank for clarifying! helped me alot

## Happy to help!

Happy to help!