Answer: 8 m/s
First let’s convert the time to seconds. There are 69 seconds in a minute so 1 minute and 40 seconds is 60 +40 second which totals to 100 seconds
Now to get the speed in meters per second we divide the total meters run by the total seconds
So the speed will be 800m/100s = 8m/s
In this sequence, we're given the first term, which is 45.
The difference between each term is -3, which means 3 will be subtracted in each term.
We're asked to find the value of the tenth term, and we can do so by using this formula:
a(n) = a(1) + d(n - 1)
Replace values.
a(10) = 45 + -3(9)
a(10) = 18
<h3>The value of the tenth term is 18.</h3>
x = the length of one piece
y = the length of the other piece
the total length is 100 cm this means
x + y = 100
one piece is 16 inches longer than the other
first we need to convert inches to cm:
1 in = 2.54 cm
16 in = 2.54*16 = 40.64
now we can write
x = y + 40.64
by solving the system of equations
x + y = 100
x = y + 40.64
we find
x = 70.32 cm
y = 29.68 cm
the lengths of the two pieces are 70.32 cm and 29.68 cm.
100 is the correct answer
Part (i)
I'm going to use the notation T(n) instead of 
To find the first term, we plug in n = 1
T(n) = 2 - 3n
T(1) = 2 - 3(1)
T(1) = -1
The first term is -1
Repeat for n = 2 to find the second term
T(n) = 2 - 3n
T(2) = 2 - 3(2)
T(2) = -4
The second term is -4
<h3>Answers: -1, -4</h3>
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Part (ii)
Plug in T(n) = -61 and solve for n
T(n) = 2 - 3n
-61 = 2 - 3n
-61-2 = -3n
-63 = -3n
-3n = -63
n = -63/(-3)
n = 21
Note that plugging in n = 21 leads to T(21) = -61, similar to how we computed the items back in part (i).
<h3>Answer: 21st term</h3>
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Part (iii)
We're given that T(n) = 2 - 3n
Let's compute T(2n). We do so by replacing every copy of n with 2n like so
T(n) = 2 - 3n
T(2n) = 2 - 3(2n)
T(2n) = 2 - 6n
Now subtract T(2n) from T(n)
T(n) - T(2n) = (2-3n) - (2-6n)
T(n) - T(2n) = 2-3n - 2+6n
T(n) - T(2n) = 3n
Then set this equal to 24 and solve for n
T(n) - T(2n) = 24
3n = 24
n = 24/3
n = 8
This means 2n = 2*8 = 16. So subtracting T(8) - T(16) will get us 24.
<h3>Answer: 8</h3>