// Numbas version: exam_results_page_options {"timing": {"timeout": {"action": "none", "message": ""}, "allowPause": true, "timedwarning": {"action": "none", "message": ""}}, "percentPass": 0, "navigation": {"reverse": true, "browse": true, "showfrontpage": false, "onleave": {"action": "none", "message": ""}, "allowregen": true, "preventleave": false, "showresultspage": "oncompletion"}, "metadata": {"description": "

Questions used in my slides for my EAMS 2016 keynote.

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a) 2

\n

b) 7t

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c) 7/6

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v = 7mph

\n

Time taken to reach C:

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Write the equation of the car's position at time t

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Find x at t=10min

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You have not given your answer to the correct precision.

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\n

Answer the following questions

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a)

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Because the car is travelling at a constant speed, the distance travelled after $t$ hours is equal to the car's velocity, $v$, multiplied by the time elapsed, $t$.

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We have been told that $v = 7$ mph.

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\\[ d(t) = v \\times t = 7 t \\]

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b)

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We have been given a time in minutes but our formula uses hours, so we first have to convert to hours.

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10 minutes is $\\frac{1}{6}$ of an hour. 

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Now, use $t = \\frac{1}{6}$ in the formula from part a:

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\\begin{align}
d(t) &= 7t \\\\
\\simplify[]{d(1/6)} &= 7 \\times \\frac{1}{6} \\\\
&= \\frac{7}{6}
\\end{align}

\n

The car has travelled $\\frac{7}{6}$ of a mile in 10 minutes.

\n

c)

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We want to find the value of $t$ when the distance travelled is $14$ miles.

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Rearrange the formula from part a:

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\\begin{align}
d(t) &= 7t \\\\
14 &= 7t \\\\
t &= 14 \\div 7 \\\\
&= 2
\\end{align}

\n

The driver takes 2 hours to reach point $B$.

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Write a formula for the car's distance in miles from point $A$, $d(t)$, in terms of the time elapsed in hours, $t$.

\n

$d(t) = $ [[0]]

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Use your formula to determine how far the driver has travelled after 10 minutes.

\n

Give your answer in miles, as a whole number or fraction.

\n

[[0]] miles

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How long does the driver take to reach point $B$?

\n

Give your answer in hours, as a whole number or fraction.

\n

[[0]] hours

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\"Car

\n

A driver travels from point $A$ to point $B$, $14$ miles away.

\n

The driver travels at a constant speed of $7$ mph.

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