The end time is 7:44. Hope this helps!
Let the three numbers be x, y and z. Then x+y+z=75.
z = 2x. y = x - 9.
Eliminate y and z by substitution: x + (x - 9) + (2x) = 75
Then 4x = 75 + 9, or 4x = 84. x = 21, y = 21 - 9 = 12, and z = 2(21) = 42.
Check: Do 21, 12 and 42 add up to 75?
Answer:
621
629
Step-by-step explanation:
We know that
sin
(
x
+
y
)
=
sin
x
cos
y
+
sin
y
cos
x
If
cos
x
=
8
17
and
sin
y
=
12
37
We can use,
cos
2
x
+
sin
2
x
=
1
and
cos
2
y
+
sin
2
y
=
1
To calculate
sin
x
and
cos
y
sin
2
x
=
1
−
cos
2
x
=
1
−
(
8
17
)
2
=
225
17
2
sin
x
=
15
17
cos
2
y
=
1
−
sin
2
y
=
1
−
(
12
37
)
2
=
1225
37
2
cos
y
=
35
37
so,
sin
(
x
+
y
)
=
15
17
⋅
35
37
+
12
37
⋅
8
17
=
621
629
Answer link
Shwetank Mauria
Nov 22, 2016
sin
(
x
+
y
)
=
621
629
or
−
429
629
depending on the quadrant in which sine and cosine lie.
Explanation:
Before we commence further, it may be mentioned that as
cos
x
=
8
17
,
x
is in
Q
1
or
Q
4
i.e.
sin
x
could be positive or negative and as
sin
y
=
12
37
,
y
is in
Q
1
or
Q
2
i.e.
cos
y
could be positive or negative.
Hence four combinations for
(
x
+
y
)
are there and for
sin
(
x
+
y
)
=
sin
x
cos
y
+
cos
x
sin
y
, there are four possibilities.
Now as
cos
x
=
8
17
,
sin
x
=
√
1
−
(
8
17
)
2
=
√
1
−
64
289
=
√
225
289
=
±
15
17
and
as
sin
y
=
12
37
,
cos
y
=
√
1
−
(
12
37
)
2
=
√
1
−
144
1369
=
√
1225
1369
=
±
35
37
Hence,
(1) when
x
and
y
are in
Q
1
sin
(
x
+
y
)
=
15
17
×
35
37
+
8
17
×
12
37
=
525
+
96
629
=
621
629
(2) when
x
is in
Q
1
and
y
is in
Q
2
sin
(
x
+
y
)
=
15
17
×
−
35
37
+
8
17
×
12
37
=
−
525
+
96
629
=
−
429
629
(3) when
x
is in
Q
4
and
y
is in
Q
2
sin
(
x
+
y
)
=
−
15
17
×
−
35
37
+
8
17
×
12
37
=
525
+
96
629
=
621
629
(4) when
x
is in
Q
4
and
y
is in
Q
1
sin
(
x
+
y
)
=
−
15
17
×
35
37
+
8
17
×
12
37
=
−
525
+
96
629
=
−
429
629
Hence,
sin
(
x
+
y
)
=
621
629
or
−
429
629
Answer:
D.)
Step-by-step explanation:
(3x4)/2 = 6
(3x4)/2 = 6
5x11= 55
4x11= 44
3x11= 33
= 146
