Answer:
Equations:
--- Cindy
--- Ruben
Solution to equation:
Time they have the same amount: 14 minutes
Number of cards they have at that time: 140 flashcards
Step-by-step explanation:
Solving (a): Variables and what they represent
The variables to use are x and y
Where x represent the minutes and y represents the number of flashcards in x minutes
Solving (b): System of linear equation
Cindy:

per minute
Total number of flashcards (y) in x minutes is:



Ruben:
per minute
Total number of flashcards (y) in x minutes is:



Solution to Equations:
Time they have the same amount.
To do this, we
expressions
i.e.

Collect Like Terms


Number of cards they have at that time.
Here, we simply substitute 14 for x in any of the equations.



or




The nickels in the envelope is $0. 12
<h3>How to determine the number</h3>
From the information given, we have that;
Dimes + nickels = $1. 20
1/4 dimes + dimes = $ 1. 35
Let dimes = d
Nickels = n
d + n = 1. 20 equation a
d/4 + d = 1. 35 equation b
Make 'd' subject from equation a
d = 1. 20 - n
Substitute into equation b
1. 20 - n/ 4 + 1. 20 - n = 1. 35
0. 3 - 0. 25n + 1. 20 - n = 1. 35
collect like terms
- 1. 25n = 1. 35 - 1. 5
- 1. 25 = - 0. 15
n = -0. 15/ -1. 25
n = 0. 12
Thus, the number of nickels in the envelope is $0. 12
Learn more about algebraic expressions here:
brainly.com/question/4344214
#SPJ1
the answer is B. A = 2.449489743, B = 1.414213562, c = 3.141592654, and D = 2.886751346. so B is the lowest.