Let d = number of dimes, q = number of quarters
<span>Sally has 20 coins in her piggy bank, so </span>
<span>d + q = 20 </span>
<span>The total amount of money is $3.05. </span>
<span>Use the value of each coin multiplied by its number to get total value </span>
<span>.10d + .25q = 3.05 </span>
<span>multiply everything by 100 to clear the decimal places </span>
<span>10d + 25q = 305 and </span>
<span>d + q = 20 </span>
<span>solve the second equation above in terms of either d or q - lets do d </span>
<span>d = 20 - q </span>
<span>sub that into the first equation </span>
<span>10d + 25q = 305 </span>
<span>10(20 - q) + 25q = 305 </span>
<span>200 - 10q + 25q = 305 </span>
<span>15q = 105 </span>
<span>q = 105/15 = 7 </span>
<span>and from above </span>
<span>d = 20 - q = 20 - 7 = 13 </span>
<span>so, there are 13 dimes and 7 quarters </span>
<span>verify with orig problem </span>
<span>13 + 7 = 20, OK, and $1.30 + $1.75 = $3.05
</span>
1. x=6
2. y=6
3. x=10
4. y=10
1.c+9= 19
2. 9-y=7
3. 5y=30
4. u-u=0
1. 2(3x2 - 5x3)
2(6-15)
2x(-9)=18
<span>Answer: a) Greater than or equal to 38 feet
b)Since there is no restriction on the perimeter there exists many possible values for the length of the deck.
Explanation: Given that the width of the deck is 29 ft.
and the perimeter of the deck is at least 134 ft.
134 = 2(length + width)
134 = (2 x length) + (2 x 29)
134 = (2 x length) + 58
2 x length = 134 - 58
2 x length = 76
length = 76 / 2
length = 38 ft
Thus, the inequality will be:
a)Length ≥ 38 ft
b)since there is no restriction on the perimeter there exists many possible values for length of deck.</span>
Answer:
100
Step-by-step explanation:
Let numbers of books be 'b' and numbers of CDs be 'c'
We can set up two equations:
Equation [1] ⇒

Equation [2] ⇒

We are solving for the number of books and the number of CDs bought
When we have two equations in terms of two different variables;

and

, that we need to solve, then this becomes a simultaneous equation problem.
First, rearrange Equation [1] to make either

or

the subject:


Then we substitute

into Equation [2]






Now we know the value of

which is

, substitute this value into

we have

Answer:
Numbers of books = 13
Numbers of CDs = 7