9514 1404 393
Answer:
a = $0.95
Step-by-step explanation:
The cost of a sharpener is 'a', and the cost of a folder is $2.80 more, so is a+2.80. The total cost of 4 sharpeners and 7 folders is ...
4a +7(a+2.80) = 30.05
11a = 10.45 . . . . . . . . . . . subtract 19.60
a = 0.95 . . . . . . . . . . . divide by 11
The cost of a sharpener is a = $0.95.
No it’s less than because it’s negative
Answer:
The rate at which the distance between them is changing at 2:00 p.m. is approximately 1.92 km/h
Step-by-step explanation:
At noon the location of Lan = 300 km north of Makenna
Lan's direction = South
Lan's speed = 60 km/h
Makenna's direction and speed = West at 75 km/h
The distance Lan has traveled at 2:00 PM = 2 h × 60 km/h = 120 km
The distance north between Lan and Makenna at 2:00 p.m = 300 km - 120 km = 180 km
The distance West Makenna has traveled at 2:00 p.m. = 2 h × 75 km/h = 150 km
Let 's' represent the distance between them, let 'y' represent the Lan's position north of Makenna at 2:00 p.m., and let 'x' represent Makenna's position west from Lan at 2:00 p.m.
By Pythagoras' theorem, we have;
s² = x² + y²
The distance between them at 2:00 p.m. s = √(180² + 150²) = 30·√61
ds²/dt = dx²/dt + dy²/dt
2·s·ds/dt = 2·x·dx/dt + 2·y·dy/dt
2×30·√61 × ds/dt = 2×150×75 + 2×180×(-60) = 900
ds/dt = 900/(2×30·√61) ≈ 1.92
The rate at which the distance between them is changing at 2:00 p.m. ds/dt ≈ 1.92 km/h
Answer:
y = -13/16
Step-by-step explanation:
<u>Given:</u>
0.8y+0.25= -0.4
<u>To Find:</u>
Solve for y
<u>Solution:</u>
Multiply both sides by 100
Simplify
Subtract 25 from both sides
Simplify
Divide both sides by 80
Simplify
Thus, y = -13/16
or in decimal form it equal y = -0.8125
<u><em>~Lenvy~</em></u>
