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lesantik [10]
3 years ago
15

Two pumps can fill a pool tank in 26 hours when working together. Alone, the second pump takes twice as long as the first to fil

l the tank. How long does it take the first pump alone to fill the tank? ____________________
Mathematics
1 answer:
vesna_86 [32]3 years ago
4 0

Answer:

Step-by-step explanation:

Let's say

d1 the outflow of the first pump

d2 the outflow of the second pump

V=1 is the volume of the tank

Since the second pump takes twice as long as the first to fill the tank,

V=1=k*d_1*t\\V=1=k*d_2*(2*t)\\==>\ d_1=2*d_2\\\\

Two pumps can fill a pool tank in 26 hours when working together:

V=1=k*(d_1+d_2)*26 \ ==> V=1=k*(3*d_2)*26 \  ==>k=\dfrac{1}{3*d_2*26} \\\\

How long does it take the first pump alone to fill the tank:

V=1=k*d_1*t=k*2*d_2*t=k*3d_2*26\\2*t=3*26\\\\t=\frac{3*26}{2} \\\\t=3*13\\\\t=39\ (hours)

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Answer:

1.067 would be the answer your looking for in this question.

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A 55% decrease followed by a 25% increase​
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Let's say the item starts off at $100.

A 55% decrease means 100%-55% = 45% of the value is still there. The item is now worth 0.45*100 = 45 dollars.

Now increase this by 25%. The long way to do this is to add 25% of 45 onto 45

(25% of 45) + (45) = 0.25*45+45 = 11.25+45 = 56.25

Or, we can multiply 45 by 1.25 since the multiplier 1.25 represents a 25% increase

1.25*45 = 56.25

-----------------------------------------------------

The item was $100, it drops to $45 after the 55% decrease, then it is $56.25 after the 25% increase.

Let's compute the percent difference

A = 100 = old value

B = 56.25 = new value

C = percent difference

C = 100*(B-A)/A

C = 100*(56.25-100)/100

C = -43.75%

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So combining a 55% decrease and a 25% increase leads to an overall decrease of 43.75%

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A shortcut is to multiply 0.45 and 1.25 to get 0.5625

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4 years ago
A person participates in a state lottery by selecting six numbers from 1 through 51. If the six numbers match the six drawn by t
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Answer:

Step-by-step explanation:

From the information given,

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Standard deviation, σ = √summation(x - mean)/n

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