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Ice is placed around a bowl of water to lower the temperature. The equation D=−7/5t+22 shows the time, t, measured in minutes and temperature, D, measured in degrees Celsius. Which statement is correct?


a)The temperature of the water decreases 5°C every 7 minutes.

b)The temperature of the water increases 7°C every 5 minutes.

c)The temperature of the ice that is around the bowl is 22°C

d)Before cooling begins, the temperature of the water is 22°C

Respuesta :

C. Is the answer troll loll

Answer:

d)Before cooling begins, the temperature of the water is 22°C

Step-by-step explanation:

Given equation that shows the temperature of the bowl after t minutes,

[tex]D=-\frac{7}{5}t+22[/tex]

Initially ( when ice is not placed ) t = 0,

So, the temperature of the water,

[tex]D=(0) + 22 = 22^{\circ}[/tex]

i.e. Option d) is correct.

If t = 7 minutes,

The temperature would be,

[tex]D=-\frac{7}{5}\times 7+22[/tex]

[tex]=-\frac{49}{5}+22[/tex]

[tex]=-\frac{49+110}{5}[/tex]

[tex]=\frac{61}{5}[/tex]

[tex]=12.2^{\circ}C[/tex]

So, the change in temperature = 12.2° - 22° = -9.8°,

Thus, option a) is incorrect.

If x = 5 minutes,

The temperature would be,

[tex]D=-\frac{7}{5}\times 5+22=-7+22 = 15^{\circ}[/tex]

Change in temperature = 15° - 22° = -7°,

So, Option b) is incorrect.

∵ The temperature of the ice must be less than 22°,

Thus, option c) is incorrect.

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