Answer:the number of nickels is 12
the the number of dimes is 15
Step-by-step explanation:
Let x represent the the number of nickels.
Let y represent the the number of dimes.
A nickel is worth 5 cents = 5/100 = $0.05
A dime is worth 10 cents = 10/100 = $0.1
Alexandra has $2.10 worth of nickels and dimes. This means that
0.05x + 0.1y = 2.10 - - - - - - - - - -1
She has a total of 27 nickels and dimes all together. This means that
x + y = 27
Substituting x = 27 - y into equation 1, it becomes
0.05(27 - y) + 0.1y = 2.10
1.35 - 0.05y + 0.1y = 2.1
- 0.05y + 0.1y = 2.1 - 1.35
0.05y = 0.75
y = 0.75/0.05 = 15
Substituting y = 15 into x = 27 - y, it becomes
x = 27 - 15 = 12
