Let n = minutes since 12:00 pm when Malory catches up to Dori.

Dori travels
(50 steps/min)*(n minutes) = 50n steps

Malory begins walking at 12:20 pm, so she walks for (n - 20) minutes. She travels
(90 steps/min)*(n - 20 min) = 90n - 1800 steps

Equate the steps traveled by Dori and Malory.
90n - 1800 = 50n
40n = 1800
n = 45 min

The time corresponding to n = 45 min is 12:45 pm

Answer: 12:45 pm

7 0

3 years ago

Um i need help with this.

blsea [12.9K]

Answer:

None of these!

Step-by-step explanation:

x + y + z = x + y + z only over here

5 0

3 years ago

Read 2 more answers

Can someone please help?!

attashe74 [19]

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4 0

3 years ago

Water pours into a tank at the rate of 2000 cm3/min. The tank is cylindrical with radius 2 meters. How fast is the height of wat

Gennadij [26K]

Volume of water in the tank:

$V=\pi (2\,\mathrm m)^2h=\pi(200\,\mathrm{cm})^2h$

Differentiate both sides with respect to time t :

$\dfrac{\mathrm dV}{\mathrm dt}=\pi(200\,\mathrm{cm})^2\dfrac{\mathrm dh}{\mathrm dt}$

V changes at a rate of 2000 cc/min (cubic cm per minute); use this to solve for dh/dt :

$2000\dfrac{\mathrm{cm}^3}{\rm min}=\pi(40,000\,\mathrm{cm}^2)\dfrac{\mathrm dh}{\mathrm dt}$

$\dfrac{\mathrm dh}{\mathrm dt}=\dfrac{2000}{40,000\pi}\dfrac{\rm cm}{\rm min}=\dfrac1{20\pi}\dfrac{\rm cm}{\rm min}$

(The question asks how the height changes at the exact moment the height is 50 cm, but this info is a red herring because the rate of change is constant.)

7 0

3 years ago