Answer:
A. 38
Step-by-step explanation:
Let d = number of dimes.
Let n = number of nickels.
First equation:
There are twice as many dimes as nickels. The number of dimes is 2 times the number of nickels. The first equation is:
<em>d = 2n</em>
Second equation:
The value of a dime is $0.10. The value of a nickel is $0.05. The value of d number of dimes is 0.1d. The value of n number of nickels is 0.05n. The total value of d dimes and n nickels is 0.1d + 0.05n. We are told the total value of her dimes and nickels is $4.75. That gives us the second equation:
<em>0.1d + 0.05n = 4.75</em>
We have two equations and two unknowns, so we can answer this question by solving a system of two equations in two unknowns.
d = 2n
0.1d + 0.05n = 4.75
We will use the substitution method.
Since d = 2n, replace d in the second equation with 2n.
0.1(2n) + 0.05n = 4.75
0.2n + 0.05n = 4.75
0.25n = 4.75
n = 4.75/0.25
n = 19
Now that we know the number of nickels, we use the equation d = 2n to find the number of dimes.
d = 2n
d = 2 * 19
d = 38
Answer: Debra had 38 dimes.
Answer:
C
Step-by-step explanation:
Answer:
n = -0.7
Step-by-step explanation:
-2n+1.8=3.2
subtract 1.8 from both sides of the equation:
-2n = 1.4
divide both sides by -2:
n = -0.7
The cat will take 0.8 seconds to catch up with the mouse
Step-by-step explanation:
Given:
The distance between the cat and the mouse = 4 feet
cat's speed = 17 feet per second.
mouse's speed = 12 feet per second
To Find:
how long will it take the cat to catch up with the mouse = ?
Solution:
We know that
distance = speed x time
Rewriting the equation for time we get
time =
now we know that distance is 4 feet
and the speed is 17 -12 = 5 feet per second
Thus the time is
= 
= 0.8 seconds
The answer is just 60 I think
