Answer:
The child has 6 dimes and 5 quarters.
Step-by-step explanation:
Let q and d represent the number of quarters and of dimes respectively.
Then q + d = 11 (Equation A), and ($0.25/quarter)q + ($0.10/dime)d = $1.85 (Equation B).
Multiply the 2nd equation by 100 to remove the decimal fractions:
25q + 10d = 185 (Equation C)
Now multiply the 1st equation by -10 to obtain -10q - 10d = -110 (Equation D), and combine this result with Equation C:
-10q - 10d = -110
25q + 10d = 185
--------------------------
15q = 75, and so q = 75/15 = 5.
According to Equation A, q + d = 11. Replacing q with 5, we get:
5 + d = 11, and so d = 6.
The child has 6 dimes and 5 quarters.
So to find the answer to this, you have to consider that

- half because half the pocket money (x) was spend on clothes, then plus 9 because that's how much extra she gained and 13 because that was the result of all the changes.
To solve this, first subtract 9 from both side, which leaves you with

and

is the same as

, so to solve this, multiply both sides of the equation by two, resulting in

. SO from this we can conclude that the weekly allowance is $8
The probability 1÷3+1÷3+1÷3=1÷9
-5x + y = -5.....multiply by -2
-4x + 2y = 2
---------------
10x - 2y = 10 (result of multiplying by -2)
-4x + 2y = 2
-----------------add
6x = 12
x = 12/6
x = 2
-5x + y = -5
-5(2) + y = -5
-10 + y = -5
y = -5 + 10
y = 5
solution is (2,5)