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GREYUIT [131]
3 years ago
8

Can you measure a time interval of 7 minutes using two sandglasses of 5 and 8 min each? If so, how?

Mathematics
1 answer:
Misha Larkins [42]3 years ago
5 0

It can be done.

You must take a few steps to set it up, but then you are able to count 7 minutes. The setup makes you be able to time 2 minutes on the 5-minute sandglass and then you do another 5 minutes on the same sandglass.

Setup:

Start both sandglasses at the same time. When the 5-minute sandglass runs out, the 8 minute sandglass has 3 minutes of sand left. At this moment, start the 5 minute sandglass again.

When the 8-minute sandglass finishes the remaining 3 minutes, the 5-minute sandglass has 2 minutes left.

Actual timing of 7 minutes:

Let the 2 minutes pass, and immediately turn over the 5-minute sandglass to count an addition 5 minutes. The last 2 minutes of the 5-minute sandglass plus an additional 5 minutes of the 5-minute sandglass add to 7 minutes.

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What number can you add to π to get a rational number?<br>PLEASE HELP thank you :P
Kryger [21]

Solution:

As we know π is an irrational number.The value of π is non terminating non repeating.

As we all know , π =\frac{\text{Circumference of circle}}{\text{Diameter}},

The fact is still we are getting an irrational number.

As , 0 is a rational number.

So, The number which when added to π, to get a rational number is (-π).

Answer → π + (-π) = 0, i.e (-π) is that number.

7 0
3 years ago
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Solve the inequality. –1/4x – 8 &lt; 3/4
Firlakuza [10]

Step-by-step explanation:

<u>Step 1:  Add 8 to both sides</u>

-\frac{1}{4}x - 8 + 8 < \frac{3}{4} + 8

-\frac{1}{4}x < \frac{35}{4}

<u>Step 2:  Multiply both sides by -4</u>

-\frac{1}{4}x * -\frac{4}{1} < \frac{35}{4} * -\frac{4}{1}

x > -35

Answer:  x > -35

3 0
3 years ago
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Given: ∠A is a straight angle. ∠B is a straight angle.
choli [55]

Given: ∠A is a straight angle. ∠B is a straight angle.

We need to Prove: ∠A≅∠B.

We know straight angles are of measure 180°.

So, ∠A and <B both would be of 180°.

It is given that ∠A and ∠B are straight angles. This means that <u>both angles are of 180°</u> because of the <u>the definition of straight angles</u>. Using <u>the definition of equality</u>, m∠A=m∠B . Finally, ∠A≅∠B by <u>definition of congruent. </u>

7 0
3 years ago
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A bus driver pays all tolls, using only nickels and dimes, by throwing one coin at a time into the mechanical toll collector.
lutik1710 [3]

Answer: a) An = An-1 + An-2

b) 55ways

Step-by-step explanation:

a) a nickel is 5 cents and a dime is 10cent so a multiple of 5 cents is the possible way to pay the tolls in both choices.

Let An represents the number of possible ways the driver can pay a toll of 5n cents, so that

An = 5n cents

Case 1: Using a nickel for payment which is 5 cents, the number of ways given as;

An-1 = 5( n-1)

Case 2: using a dime which is two 5 cents, the number of ways is given as;

An-2 = 5(n-2)

Summing up the number of ways, we have

An = An-1 + An-2

From the relation,

If n= 0, Ao= 1

n =1, A1= 1

b) 45 cents paid in multiples of 5cents will give us 9 ways(A9)

From the relation, we have that

Ao = 1

A1 = 1

An =An-1 + An-2

Ao = 1

A1 = 1

A2 = A1+Ao = 1+1= 2

A3 = A2 + A1 = 3

A4 = A3+A2=5

A5=A4+A3=8

A6=A5+A4=13

A7 =A6+A5 = 21

A8= A7+A6= 34

A9= A8+A7= 55

So there are 55ways to pay 45cents.

4 0
3 years ago
A lake contain 900 gallons of water. The city is pumping water into the lake at a rate of 30 gallons per minute. Which expressio
boyakko [2]

Answer:

900 + 12 x 30

Step-by-step explanation:

4 0
3 years ago
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