Answer:
It’s 60miles
Step-by-step explanation:
We assume the trip is "d" miles and that the "extra hour" refers to the additional time that a current of 2 mph would add. That is, we assume the reference time is for a current of 0 mph.
The time with no current is ...
time1 = distance/speed
time1 = d/12 . . . . hours
With a current of 2 mph in the opposite direction, the time is ...
time2 = d/(12 -2) = d/10
The second time is 1 hour longer than the first, so we have ...
time2 = 1 + time1
d/10 = 1 + d/12
6d = 60 + 5d . . . . multiply by 60
d = 60 . . . . . . . . . subtract 5d
The one-way distance is 60 miles.
Answer:
20, 60, 15
Step-by-step explanation:
Let the third number be n, then
The first number is n + 5 and the second number is 4n
Sum the 3 numbers and equate to 95, that is
n + 5 + 4n + n = 95 ← collect like terms on left side
6n + 5 = 95 ( subtract 5 from both sides )
6n = 90 ( divide both sides by 6 )
n = 15
Thus
The first number is 15 + 5 = 20
The second number is 4 × 15 = 60
The third number is 15
Answer:
-26/8+7=15/4 or 3 3/4
Step-by-step explanation:
Use the quadratic formula to find:
x
=
1
±
√
85
5
Explanation:
5
x
2
−
10
x
−
12
is of the form
a
x
2
+
b
x
+
c
with
a
=
5
,
b
=
−
10
and
c
=
−
12
This has discriminant
Δ
given by the formula:
Δ
=
b
2
−
4
a
c
=
(
−
10
)
2
−
(
4
×
5
×
−
12
)
=
100
+
240
=
340
=
2
2
⋅
85
This is positive, but not a perfect square, so the quadratic equation has a pair of irrational roots, given by the quadratic formula:
x
=
−
b
±
√
b
2
−
4
a
c
2
a
=
−
b
±
√
Δ
2
a
=
10
±
√
340
10
=
10
±
2
√
85
10
=
1
±
√
85
5
