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Ronch [10]
3 years ago
15

You find 72 coins consisting only of nickels, dimes, and quarters, with a face value of $10.20. However, the coins all date from

1919, and are worth considerably more than their face value. A coin dealer offers you $10 for each nickel, $20 for each dime, and $15 for each quarter, for a total of $1,060. How many nickels did you find?
Mathematics
1 answer:
Oliga [24]3 years ago
7 0

Answer:

You have found 24 nickels.

Step-by-step explanation:

Let N be the number of nickles, D be the number of dimes and Q be the number of quarters. The number of coins and their face values are given by the following expressions, respectively:

N+D+Q=72\\0.05N+0.10D+0.25Q=10.20

As of now we have three variables and two expressions, the final expression needed to solve the linear system is given by the amount offered by the coin dealer:

10N+20D+15Q=1,060

Solving the linear system:

N+D+Q=72\\5N+10D+25Q=1,020\\10N+20D+15Q=1,060\\\\10N-10N+20D-20D+15Q-50Q=1,060-(2*1,020)\\-35Q=-980\\Q=28\\\\5N-10N+10D-10D+25Q-10Q=1,020-720\\-5N+15Q=300\\-5N=300-(15*28)\\N=24

You have found 24 nickels.

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Two bicyclists were racing toward each other when they were 98 miles apart. Three hours later they did not meet yet and the dist
lesya [120]

Let, speed of 1st bicyclist is x.

So, speed of 2nd bicyclist is x-3 .

We know, relative speed when two objects moves towards each other :

v = x + ( x-3 )\\\\v = 2x - 3

Now, distance travelled in 3 hours is (98-2) miles .

So,

2x-3 = \dfrac{96}{3}\\\\2x - 3 = 32\\\\2x = 35\\\\x = 17.5\ mph

Therefore, speed of bikes are 17.5 mph and 14.5 mph.

Hence, this is the required solution.

5 0
3 years ago
Y=4, -4y + 5 evaluate it please​
Shtirlitz [24]

Answer:

Step-by-step explanation:

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4

−

4

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5

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9

−

4

8 0
3 years ago
Points Pand Q lie in plane A. How many lines contain P
jeka94

Answer:

The correct answer is :

1. Line PQ (One line PQ).

Step-by-step explanation:

The first step to solve this question is to draw the plane A with the points P and Q lying on it.

We know that given two different points there is only one line that contains this two different points.

Let's analyze each option.

''2. Lines PQ and QP''

This option is wrong because there aren't two different lines. In fact it is only one line that can be named line PQ or line QP.

''3. The 2 lines PQ and QP plus another line that does not lie in plane A.''

This option is assuming that exist three lines that contain P and Q. This option is also wrong.

''1. Line PQ''

This option is correct. It will be clarify with the drawing I will attach.

''We can't name them all!''

This option is assuming that exist infinite lines that contain P and Q. This option is wrong.

In the drawing I call the line that contains P and Q as line L.

Given that P and Q lie in plane A necessarily the line L must lie on the plane A.

8 0
3 years ago
Suppose x is a normally distributed random variable with a mean of 12 and a standard deviation of 3. The probability that x equa
Contact [7]

Answer:

The probability that x equals 19.62 is 0

Step-by-step explanation:

Normal Probability Distribution:

Problems of normal distributions can be solved using the z-score formula.

In a set with mean \mu and standard deviation \sigma, the z-score of a measure X is given by:

Z = \frac{X - \mu}{\sigma}

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the p-value, we get the probability that the value of the measure is greater than X.

In the normal probability distribution, the probability of an exact value, that is, P(X = x) is 0. Thus, the probability that x equals 19.62 is 0

8 0
3 years ago
Need help with number 4
anastassius [24]
Find the common denominators. for the miles 5 and 3 go into 15. so 2/5 times 3 is 6/15. and 2/3 times 5 is 10/15. for the hours 5 and 9 go into 45. 1/5 times 9 is 9/45. and 2/9 times 5 is 10/45. so Susan ran 6/15 of a mile in 9/45 of an hour. and Kim ran 10/15 of a mile in 10/45 of an hour.

so Kim ran 3 miles in an hour. Susan ran 2 miles in an hour.
8 0
3 years ago
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