Answer:
y = 6
x = 2
Step-by-step explanation:
rearrange the first equation in terms of x
x = (y - 2)/2
substiute x in the second equation
y = -5[(y-2)/2] +16
Now simpilify and solve for y
y = (-5y + 10)/2 +16
y = -5/2y + 5 + 16
y + 5/2y = 5 + 16
3.5y = 21
y = 6
Now substitue y in the first equation to solve for x
x = (6 - 2)/2
x = 2
Answer: D. n + q = 20
5n + 25q = 300
Step-by-step explanation:
Let n represent the number of nickels that you have.
Let q represent the number of quarters that you have.
Suppose you have 20 coins. It means that
n + q = 20
The total value of the coins is $3. The value of a quarter is $0.25 and the value if a nickel is $0.05. Therefore, the equation would be
0.05n + 0.25q = 3
Multiplying both sides of the equation by 100, it becomes
5n + 25q = 300
The correct option is
D. n + q = 20
5n + 25q = 300
Use the calculator to find the Product
Let the original 2-digit number be xy.
Because 5 times the sum of the digits is 13 less than the number, therefore
5(x + y) = 10x + y - 13
5x + 5y = 10x + y - 13
-5x + 4y = - 13 (1)
The number with reversed digits is yx.
Because 4 times the sum of the digits is 21 less than the reversed 2-digit number, therefore
4(x + y) = 10y + x - 21
4x + 4y = 10y + x - 21
3x - 6y = -21
x - 2y = -7
x = 2y - 7 (2)
Substitute (2) into (1).
-5(2y - 7) + 4y = -13
-10y + 35 + 4y = -13
-6y = -48
y = 8
From (3), obtain
x = 2*8 - 7 = 9
Answers:
The original 2-digit number is 98
The reversed 2-digit number is 89
The difference between the original and the reversed 2-digit numbers is
98 - 89 = 9
