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madreJ [45]
2 years ago
6

Jo jo has a total amount of $12.45 in quarters and dimes in his pocket. he has a total of 60 coins. how many quarters and dimes

does jo jo have?
a. 42 quarters and 18 dimes b. 43 quarters and 17 dimes
c. 44 quarters and 16 dimes d. 41 quarters and 19 dimes
e. 40 quarters and 20 dimes

NEED ANSWERED ASAPP!!!

Mathematics
1 answer:
baherus [9]2 years ago
8 0

Given:

Total number of coins (Quarters and dimes) = 60

Total amount = $12.45

To find:

The number of quarters and dimes.

Solution:

Let x be the number of quarters and y be the number of dimes.

We know that,

1 quarter = 0.25 dollar

1 dime = 0.10 dollar

Total coins: x+y=60               ...(i)

Total amount: 0.25x+0.10y=12.45             ...(ii)

From (i), we get

y=60-x          ...(iii)

Putting this value in (ii), we get

0.25x+0.10(60-x)=12.45

0.25x+6-0.10x=12.45

0.25x-0.10x=12.45-6

0.15x=6.45

Divide both sides by 0.15.

x=\dfrac{6.45}{0.15}

x=43

Putting x=43 in (iii), we get

y=60-43

y=17

So, the number of quarters is 43 and the number of dimes is 17.

Therefore, the correct option is b.

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Katyanochek1 [597]

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Step-by-step explanation:

These problems make use of three rules of exponents:

a^ba^c=a^{b+c}\\\\(a^b)^c=a^{bc}\\\\a^{-b}=\dfrac{1}{a^b} \quad\text{or} \quad a^b=\dfrac{1}{a^{-b}}

In general, you can work the problem by using these rules to compute the exponents of each of the variables (or constants), then arrange the expression so all exponents are positive. (The last problem is slightly different.)

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1. There are no "a" variables in the numerator, and the denominator "a" has a positive exponent (1), so we can leave it alone. The exponent of "b" is the difference of numerator and denominator exponents, according to the above rules.

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2. 1 to any power is still 1. The outer exponent can be "distributed" to each of the terms inside parentheses, then exponents can be made positive by shifting from denominator to numerator.

\left(\dfrac{1}{4ab}\right)^{-2}=\dfrac{1}{4^{-2}a^{-2}b^{-2}}=16a^2b^2

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3. One way to work this one is to simplify the inside of the parentheses before applying the outside exponent.

\left(\dfrac{4mn}{m^{-2}n^6}\right)^{-2}=\left(4m^{1-(-2)}n^{1-6}}\right)^{-2}=\left(4m^3n^{-5}}\right)^{-2}\\\\=4^{-2}m^{-6}n^{10}=\dfrac{n^{10}}{16m^6}

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4. This works the same way the previous problem does.

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3 years ago
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kipiarov [429]

Answer:

0.68269

Step-by-step explanation:

When we are to find the z score for population where a random sample is picked, the z.score formula we use is

z = (x-μ)/Standard error, where

x is the raw score,

μ is the population mean

Standard error = σ/√n

σ is the population standard deviation

n = random number of samples

For : x = 38 minutes, μ = 40, σ = 10, n = 5

z = 38 - 40/10 /√25

= -2/10/5

= -2/2

= -1

Determining the probability value using z table

P(x = 38) = P(z = -1)

= 0.15866

For : x = 42 minutes, μ = 40, σ = 10, n = 25

z = 42 - 40/10 /√25

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Determining the probability value using z table

P(x = 42) = P(z = 1)

= 0.84134

The probability that their average waiting time will be between 38 and 42 minutes is calculated as

P(-Z<x<Z)

= P(-1 < x < 1)

= P(z = 1) - P(z = -1)

= 0.84134 - 0.15866

= 0.68269

Therefore, the probability that their average waiting time will be between 38 and 42 minutes is 0.68269

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3 years ago
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inessss [21]

Step-by-step explanation:

Apples cost four times as much as oranges per pound.

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5 0
3 years ago
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