Answer:
(a) 0.05z +0.25(54 -z) = 6.90
Explanation:
Where z is the number of nickels the student has, an equation can be written that expresses the value of all coins in terms of z.
We assume suggested equations are ...
- 0.05z +0.25(54 -z) = 6.90
- 54z = 6.90
- 0.05z +16 = 6.90
- 0.05 +0.25(54 -z) = 6.90
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value of nickels
If each of z nickels has the value $0.05, then their total value will be ...
z × ($0.05)
If we remember that our values are in dollars, we can write this without the dollar sign as ...
0.05z
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value of quarters
Each of the 54 coins that is not a nickel will be a quarter, worth $0.25. There will be (54-z) of them, so their value in dollars is ...
0.25(54 -z)
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total value
An equation we can use to find the value of z is the one that relates these individual coin values to the total value of all the coins:
value of nickels + value of quarters = total value
0.05z +0.25(54 -z) = 6.90 . . . . . . an equation for determining z
This matches the first choice of our presumed list of choices for the equation.