Let the width be x, the length is then 3x-10
Area of a rectangle is length times width: x(3x-10)=77 => 3x^2-10x-77=0
Factor this quadratic equation: (x-7)(3x+11)=0 =.x=7 or x=-11/3
width cannot be negative, so the only answer is x=7
width is 7m, length is 11m
Answer:
Rate of current is 3 miles per hour and speed of the boat in still water is 7 miles per hour.
Step-by-step explanation:
This question is incomplete; find the complete question here.
A boat travels 20 miles upstream in 5 hours. Going downstream, it can travel 50 miles in the same amount of time. Find the speed of the current and the speed of the boat in still water.
Let the speed boat in the still water = x miles per hour
and the speed (rate) of the current = y miles per hour
Speed of the boat to go upstream (against the current) will be = (x - y)miles per hour
Since boat takes 5 hours downstream to travel 50 miles then from the formula,


(x + y) = 10 -------(1)
Boat takes 5 hours to travel 50 miles upstream then,

5 = 
x - y = 4 -----(2)
By adding equation (1) and question (2)
(x + y) + (x - y) = 14
2x = 14
x = 7 miles per hour
From equation (1),
7 + y = 10
y = 3 miles per hour
Therefore, Rate of current is 3 miles per hour and speed of the boat in still water is 7 miles per hour.
Answer:
Step-by-step explanation:
The actual sum was 3 DVDs and 1 BlueRay.
x + y = 4
2x + 5y = 11
No systems are given, but you can look for something that looks like the above 2 equations.
Answer:
D
Step-by-step explanation:
12 times 2 times 7
equals 168