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3 years ago

gabby's piggy bank contains dimes and nickels worth $6.40. If she has 84 coins in all, how many of each does she have?

1 answer:

5 0

If we let Q be the number of quarters and N be number of nickels, this is the formula we would use:
[1] 25Q + 5N = 635 (using cents instead of dollars)

We also know something about Q and N.

[2] Q + N = 51

So multiply both sides of the second equation by 5. The reason we do this is because we're going to need to cancel out one of the variables (either Q or N) to solve for the other one. If we multiply times 5, we'll have 5N in both equations.
5Q + 5N = 255

Now we have two equations, and the second one can be subtracted from the first.

25Q + 5N = 635
-(5Q + 5N) = -255
---------------------
20Q = 380
so
Q = 19

There are 19 quarters.

And since there are 51 coins in all, 51-19 = 32 nickels.

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3 years ago

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3 years ago

g A coffee-dispensing machine is supposed to deliver eight ounces of liquid into each paper cup, but a consumer believes that th

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Answer: Reject the eight- ounces claim.

Step-by-step explanation:

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As per given ,

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4 years ago

F(x) = x2<br> What is f(x) + f(x) + f(x)?

Yuliya22 [10]

Answer:

if you meant x squared the answer is 3x^2

Step-by-step explanation:

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3 years ago

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The temperature fell from 0 Degrees Fahrenheit to 15 and one-half Degrees Fahrenheit below 0 in 5 and three-fourths hours. Wen t

Kryger [21]

Answer:

The correct answer will be:

$-\dfrac{62}{23}$

Step-by-step explanation:

It is given that :

Initial temperature, $T_1 = 0^\circ F$

Final temperature,

$T_2 = -15\dfrac{1}{2}^\circ F\\\Rightarrow T_2 = -\dfrac{15\times 2+1}{2} ^\circ F\\\Rightarrow T_2 = -\dfrac{31}{2} ^\circ F$

Time taken :

$5\dfrac{3}{4}\ hrs = \dfrac{5 \times 4+3}{4}\ hrs = \dfrac{23}{4}\ hrs$

Change in temperature per hour:

$\dfrac{\text{Difference of temperature}}{\text{Total Time Taken}}\\\Rightarrow \dfrac{T_2-T_1}{\text{Total Time Taken}}$

Putting the values of temperatures and time:

$\dfrac{\dfrac{-31}{2}-0}{\dfrac{23}{4}}\\\Rightarrow \dfrac{\dfrac{-31}{2}}{\dfrac{23}{4}}\\\Rightarrow \dfrac{-31 \times 4}{2 \times 23}} \text{---- Error done by Wen at this step}\\\Rightarrow \dfrac{-31 \times 2}{23}}\\\Rightarrow \dfrac{-62}{23}}$

The error done by Wen was during calculating the values of fraction.

So, the correct answer is : $\frac{-62}{23}}$ instead of $\frac{-713}{8}$

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4 years ago

Read 2 more answers