MHB (Fractions) How many cookies did Meiling bake

  • Thread starter Thread starter Johnx1
  • Start date Start date
  • Tags Tags
    Fractions
Johnx1
Messages
48
Reaction score
0
Meiling baked some cookies. 5/7 of the cookies were butter cookies and the rest were green tea cookies. She gave away 3/4 of the butter cookies and 1/4 of the green tea cookies. After she ate 9 green tea cookies, she had an equal number of butter cookies and green tea cookies left. How many cookies did Meiling bake?

My work:

Number of butter cookies = B
Number of Green Tea cookies = G
Number of total cookies = T (not sure about this one)

We know there are 2/7G of the total cookies because 5/7B

Then I did 3/4B = 1/4G - 9.

I tried different ways, but I couldn't find a correct way to do it.
 
Mathematics news on Phys.org
Johnx said:
Meiling baked some cookies. 5/7 of the cookies were butter cookies and the rest were green tea cookies. She gave away 3/4 of the butter cookies and 1/4 of the green tea cookies. After she ate 9 green tea cookies, she had an equal number of butter cookies and green tea cookies left. How many cookies did Meiling bake?

My work:

Number of butter cookies = B
Number of Green Tea cookies = G
Number of total cookies = T (not sure about this one)

We know there are 2/7G of the total cookies because 5/7B

Then I did 3/4B = 1/4G - 9.

I tried different ways, but I couldn't find a correct way to do it.

let x = total number of cookies

number of butter cookies = 5x/7

number of tea cookies = 2x/7

number of butter cookies left = (1/4)(5x/7) = 5x/28

number of tea cookies left = (3/4)(2x/7) - 9 = 3x/14 - 9

5x/28 = 3x/14 - 9

5x = 6x - 252

x = 252

check ...

B = (5/7)252 = 180

T = (2/7)252 = 72

gave away (3/4)180 = 135 ... number of butter cookies left = 45

gave away (1/4)72 + ate 9 = 27 ... number of tea cookies left = 45
 
skeeter said:
number of butter cookies left = (1/4)(5x/7) = 5x/28

number of tea cookies left = (3/4)(2x/7) - 9 = 3x/14 - 9

I see where I made the mistake. I had to times the number of cookies that were left.

Thank you.
 

Thread 'What Exactly is Dirac’s Delta Function? - Insight'

Insights auto threads is broken atm, so I'm manually creating these for new Insight articles. In Dirac’s Principles of Quantum Mechanics published in 1930 he introduced a “convenient notation” he referred to as a “delta function” which he treated as a continuum analog to the discrete Kronecker delta. The Kronecker delta is simply the indexed components of the identity operator in matrix algebra Source: https://www.physicsforums.com/insights/what-exactly-is-diracs-delta-function/ by...
View full post »

Thread 'Fermat's Last Theorem'

Fermat's Last Theorem has long been one of the most famous mathematical problems, and is now one of the most famous theorems. It simply states that the equation $$ a^n+b^n=c^n $$ has no solutions with positive integers if ##n>2.## It was named after Pierre de Fermat (1607-1665). The problem itself stems from the book Arithmetica by Diophantus of Alexandria. It gained popularity because Fermat noted in his copy "Cubum autem in duos cubos, aut quadratoquadratum in duos quadratoquadratos, et...
View full post »
Thread 'Imaginary Pythagorus'

Thread 'Imaginary Pythagorus'

I posted this in the Lame Math thread, but it's got me thinking. Is there any validity to this? Or is it really just a mathematical trick? Naively, I see that i2 + plus 12 does equal zero2. But does this have a meaning? I know one can treat the imaginary number line as just another axis like the reals, but does that mean this does represent a triangle in the complex plane with a hypotenuse of length zero? Ibix offered a rendering of the diagram using what I assume is matrix* notation...
View full post »

Similar threads

How Many Cookies Did Tim Eat on the First Day?
Replies
1
Views
3K
MHB Fraction word problem: how many rows are devoted to each plant
Replies
2
Views
3K
MHB John's Cupcake Challenge: Finding the Perfect Distribution
Replies
3
Views
3K
MHB How many stickers did Angel and Kareem have altogether?
Replies
1
Views
872
MHB Fractions/brackets/parentheses and powers.
Replies
3
Views
3K
MHB How many envelopes did Elias have at first
Replies
1
Views
927
MHB How Many Dogs Did the Pet Store Sell in March?
Replies
3
Views
1K
MHB Fraction Multiplication: How to Multiply Fractions and Mixed Numbers
Replies
3
Views
3K
Photo Contest - Half-Baked Ideas (11/14-11/20)
Replies
8
Views
2K
MHB How many audiences at a musical
Replies
2
Views
1K

Hot Threads

Recent Insights

Back
Top