Lets start with the chain of 3's:
18 = 3 + 3 + 3 + 3 + 3 + 3
But, we know that
3 + 3 = 2 + 2 + 2
Sol, let's replace 3 + 3 by 2 + 2 + 2 one by one.
Hence, the possible ways of combinations are listed below:
18 = 3 + 3 + 3 + 3 + 2 + 2 + 2 (1)
18 = 3 + 3 + 2 + 2 + 2 + 2 + 2 + 2 (2)
Therefore, there are two combinations of 2- and 3- point shots that could total 18 points.
Answer:
√
8
≈
3
Explanation:
Note that:
2
2
=
4
<
8
<
9
=
3
2
Hence the (positive) square root of
8
is somewhere between
2
and
3
. Since
8
is much closer to
9
=
3
2
than
4
=
2
2
, we can deduce that the closest integer to the square root is
3
.
We can use this proximity of the square root of
8
to
3
to derive an efficient method for finding approximations.
Consider a quadratic with zeros
3
+
√
8
and
3
−
√
8
:
(
x
−
3
−
√
8
)
(
x
−
3
+
√
8
)
=
(
x
−
3
)
2
−
8
=
x
2
−
6
x
+
1
From this quadratic, we can define a sequence of integers recursively as follows:
⎧
⎪
⎨
⎪
⎩
a
0
=
0
a
1
=
1
a
n
+
2
=
6
a
n
+
1
−
a
n
The first few terms are:
0
,
1
,
6
,
35
,
204
,
1189
,
6930
,
...
The ratio between successive terms will tend very quickly towards
3
+
√
8
.
So:
√
8
≈
6930
1189
−
3
=
3363
1189
≈
2.828427
Answer:
10* 299.99=2999.9
2999.9/100=29.999
this would round up to 30, so Brittany saved $30. : )
