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This year tim filled his swimming pool in 16 h less time than the previous year by adding a second garden hose with a faster flow rate. The second garden hose can fill the swimming pool in 16.25 h working alone

Sagot :

Answer:

It takes 10 hours using both hoses to fill the pool

Step-by-step explanation:

The rate of the first hose = 1/(x+16)

The rate of the second faster hose is given =1/16.25 = 1/(65/4)=4/65

The combined work rate is 1/x

the sum of the individul work rates equls the combined work rate

1/(x+16) +(4/65) = (1/x)

Multiply each term by the LCM which is  (x+16)(65)(x)

The result is:   65x+4x^2+64x=65x+1040

Simplify by subracting 65x from both sides of the equation.

4x^2+64x=1040

Next divide every term by 4

x^2 +16x = 260

subtract 260 from both sides

x^2+16x-260=0

The factors of 260 are: (1 x 260), (2 x 130), (4 x 65), (5 x 52), (10 x 26), (16x 30)

the two that have a difference of 16 are (10 x 26)

the equation factors to

(x +26) (x - 16) = 0

so x = -26 or x = 10

Since you can not have negative time x can not equal -26 it is an extraneous root.

So, the only solution is x =10

It took 10 hours to fill the pool with both hoses running.