Answer: Downhill:10mph Uphill:5mph
Step-by-step explanation:
We are looking for Dennis’s downhill speed.
Let
r=
Dennis’s downhill speed.
His uphill speed is
5
miles per hour slower.
Let
r−5=
Dennis’s uphill speed.
Enter the rates into the chart. The distance is the same in both directions,
20
miles.
Since
D=rt
, we solve for
t
and get
t=
D
r
.
We divide the distance by the rate in each row and place the expression in the time column.
Rate
×
Time
=
Distance
Downhill
r
20
r
20
Uphill
r−5
20
r−5
20
Write a word sentence about the time.
The total time traveled was
6
hours.
Translate the sentence to get the equation.
20
r
+
20
r−5
=6
Solve.
20(r−5)+20(r)
40r−100
0
0
0
=
=
=
=
=
6(r)(r−5)
6
r
2
−30r
6
r
2
−70r+100
2(3
r
2
−35r+50)
2(3r−5)(r−10)
Use the Zero Product Property.
(r−10)=0
r=10
(3r−5)=0
r=
5
3
The solution
5
3
is unreasonable because
5
3
−5=−
10
3
and his uphill speed cannot be negative. So, Dennis's downhill speed is
10
mph and his uphill speed is
10−5=5
mph.
Check. Is
10
mph a reasonable speed for biking downhill? Yes.
Downhill:
10 mph
5 mph⋅
20 miles
5 mph
=20 miles
Uphill:
10−5=5 mph
(10−5) mph⋅
20 miles
10−5 mph
=20 miles
The total time traveled was
6
hours.
Dennis’ downhill speed was
10
mph and his uphill speed was
5
mph.
Answer: The correct option is (C) Packages x 3 = Pens
Step-by-step explanation: Given that each package of pens contains 3 pens.
We are to choose the correct mathematical relation between number of pens and number of packages.
Let, n represents the number of pens and N represents the number of packages.
Then, according to the given information, we have
Thus, the correct relation is
Packages x 3 = Pens.
Option (C) is CORRECT.
The two enclosures will need three equal fences coming out from the wall and meeting another fence running parallel to the wall. If the fences coming out from the wall are x metres long the parallel fence will be (132 - 3x) metres long.
The area A = x(132 - 3x) = 132x - 3x^2
The derivative of A = zero when 132 - 6x = 0 which means the maximum area is when x = 22m
The maximum area = 22 x (132 - 3 x 22) = 1452 m^2
If you don’t know how to find derivatives then you could sketch the graph of y = x(132 - 3x).
This is an inverted parabola (hill) with x intercepts at 0 and 132/3 = 44.
The maximum point (top of the hill) is halfway between 0 and 44 I.e. 22m
Try any other value for x and the area will be smaller.
Answer: Length of his shadow is 18 feet.
Step-by-step explanation:
Since we have given that
Length of tall monument = 64 foot
Length of shadow = 16 feet
Length of pole where Kyle is standing = 6 feet 3 inch = 72 inches
So, we need to find the length of its shadow.
So, according to question, we get that
Hence, length of his shadow is 18 feet.
Answer:
digestive would be stomach, excretion is the big and small intestines
Step-by-step explanation:
stomach digests food, your intestines process whatever is left till you excrete
