All categories

3 years ago

A newspaper carrier has $1.80 in change. He has two more quarters than dimes but three times as many nickels as quarters. How ma

ny coins of each type does he have?

Mathematics

1 answer:

Mazyrski [523]3 years ago

3 0

$1\ quarter=\$0.25\\1\ dime=\$0.10\\1\ nickel=\$0.05\\\\q\ \ \ \rightarrow\ \ \ the\ number\ of\ the\ quarters\\d\ \ \ \rightarrow\ \ \ the\ number\ of\ the\ dimes\\n\ \ \ \rightarrow\ \ \ the\ number\ of\ the\ nickels\\\\q=2d\ \ \ and\ \ \ n=3q\ \ \ \Rightarrow\ \ \ n=3\cdot 2d=6d\\\\q\cdot0.25+d\cdot0.10+n\cdot 0.03=1.80\\\\2d\cdot0.25+d\cdot0.1+6d\cdot0.05=1.8\\\\$

$0.5d+0.1d+0.3d=1.8\\\\0.9d=1.8\ \ \ \Rightarrow\ \ \ d=2\ \ \ \Rightarrow\ \ \ q=2\cdot2=4\ \ \ and\ \ \ n=6\cdot2=12\\\\Ans.\ 4\ quarters,\ 2\ dimes,\ 12\ nickels$

You might be interested in

What is .64 divided by 3.456

Simora [160]

the answer to this question would be 0.185185185185185

6 0

3 years ago

Plz help with 9 and 10

GenaCL600 [577]

Answer:

Tony can buy three games with his savings over two months and Alice can buy six concert tickets.

Step-by-step explanation:

Over two months, Tony has watched a total of 53.6 hours of television (35.4 + 18.2). If he save $2.50 for each hour, we can multiply his total hours by the amount per hour, or 53.6 x 2.50 = $134.00. Since each game that Tony wants to buy costs $35.75, we need to divide his total savings by the cost of each game, or 134/35.75 = 3.75. Since Tony can't buy a portion of the game, the most amount of games he can buy is 3. Alice watched a total of 48.4 hours of television (21.8 + 26.6). If she also saves $2.50 per hour, then her total savings is 2.50 x 48.4 = $121.00. Since her concert tickets are $17.50 a piece, we divide her total savings: 121/17.50 = 6.9. Alice can also not buy a partial ticket, so the total amount she can buy is 6.

4 0

3 years ago

27. 8 minus the product of 9 and r

Tems11 [23]

8-9r is the answer to this

6 0

3 years ago

There are 1/3 gallon of water in a 3-gallon container. What fraction of the container is filled?

ivanzaharov [21]

Answer:

1/9 of a container

3 0

3 years ago

Implicit differentiation Please help

Anvisha [2.4K]

Answer:

$y''(-1) =8$

General Formulas and Concepts:

Pre-Algebra

Order of Operations: BPEMDAS

Brackets
Parenthesis
Exponents
Multiplication
Division
Addition
Subtraction

Left to Right

Equality Properties

Algebra I

Factoring

Calculus

Implicit Differentiation

The derivative of a constant is equal to 0

Basic Power Rule:

f(x) = cxⁿ
f’(x) = c·nxⁿ⁻¹

Product Rule: $\frac{d}{dx} [f(x)g(x)]=f'(x)g(x) + g'(x)f(x)$

Chain Rule: $\frac{d}{dx}[f(g(x))] =f'(g(x)) \cdot g'(x)$

Quotient Rule: $\frac{d}{dx} [\frac{f(x)}{g(x)} ]=\frac{g(x)f'(x)-g'(x)f(x)}{g^2(x)}$

Step-by-step explanation:

Step 1: Define

-xy - 2y = -4

Rate of change of the tangent line at point (-1, 4)

Step 2: Differentiate Pt. 1

Find 1st Derivative

Implicit Differentiation [Product Rule/Basic Power Rule]: $-y - xy' - 2y' = 0$
[Algebra] Isolate y' terms: $-xy' - 2y' = y$
[Algebra] Factor y': $y'(-x - 2) = y$
[Algebra] Isolate y': $y' = \frac{y}{-x-2}$
[Algebra] Rewrite: $y' = \frac{-y}{x+2}$

Step 3: Find y

Define equation: $-xy - 2y = -4$
Factor y: $y(-x - 2) = -4$
Isolate y: $y = \frac{-4}{-x-2}$
Simplify: $y = \frac{4}{x+2}$

Step 4: Rewrite 1st Derivative

[Algebra] Substitute in y: $y' = \frac{-\frac{4}{x+2} }{x+2}$
[Algebra] Simplify: $y' = \frac{-4}{(x+2)^2}$

Step 5: Differentiate Pt. 2

Find 2nd Derivative

Differentiate [Quotient Rule/Basic Power Rule]: $y'' = \frac{0(x+2)^2 - 8 \cdot 2(x + 2) \cdot 1}{[(x + 2)^2]^2}$
[Derivative] Simplify: $y'' = \frac{8}{(x+2)^3}$

Step 6: Find Slope at Given Point

[Algebra] Substitute in x: $y''(-1) = \frac{8}{(-1+2)^3}$
[Algebra] Evaluate: $y''(-1) =8$

6 0

3 years ago

Read 2 more answers