Answer:
9 nickels
Step-by-step explanation:
Changing a quarter to a nickel decreases the value of the sum by $0.20.
When all quarters are changed to nickels and vice versa, the total value will change by the number of excess quarters. That number is ...
($5.95 -3.35)/(0.20) = 2.60/0.20 = 13
The remaining change is made up of equal numbers of nickels and quarters. That amount of change is ...
$5.95 -13·0.25 = 2.70
A quarter and nickel together total $0.30, so there must be $2.70/$0.30 = 9 such pairs of coins.
There are 9 nickels and 22 quarters.
_____
If you don't want to reason through the problem, you can write equations. Let n and q represent the numbers of nickels and quarters, respectively. Then you have ...
0.05n + 0.25q = 5.95
0.25n + 0.05q = 3.35
Multiplying the second equation by 5 and subtracting the first gives ...
5(0.25n +0.05q) -(0.05n +0.25q) = 5(3.35) -(5.95)
1.20n = 10.80
10.80/1.20 = n = 9
The number of nickels is 9.
Answer:
1: 75
Step-by-step explanation:
20cm : 15m
Convert meters to cm
1 meter = 100 cm
15m = 15 x 100 = 1500 cm
20cm:1500cm
Divide both sides of the ratio by 20
=> 1 : 1500/20 = 1: 75
Answer:
(9 x - 7 y) (9 x + 7 y)
Step-by-step explanation:
Factor the following:
81 x^2 - 49 y^2
Hint: | Express 81 x^2 - 49 y^2 as a difference of squares.
81 x^2 - 49 y^2 = (9 x)^2 - (7 y)^2:
(9 x)^2 - (7 y)^2
Hint: | Factor the difference of two squares.
Factor the difference of two squares. (9 x)^2 - (7 y)^2 = (9 x - 7 y) (9 x + 7 y):
Answer: (9 x - 7 y) (9 x + 7 y)
If it is two negatives its a positive, if its a negative and one positive it will be negative. but if its two positive its positive
(-)+(-)=(+)
(-)+(+)=(-)
(+)+(+)=(+)
