Answer:
1/2
Step-by-step explanation:
There are 4 nickels, 2 dimes, and 6 quarters. That means a total of 12 coins, half of which are quarters.
(realistically, if she wanted to, she could probably get a quarter every time if she felt for the size)
The answers are 1, 2, 5, and 7
<span>An equation is a statement of equality „=‟ between two expression for particular</span>values of the variable. For example5x + 6 = 2, x is the variable (unknown)The equations can be divided into the following two kinds:Conditional Equation:<span>It is an equation in which two algebraic expressions are equal for particular</span>value/s of the variable e.g.,<span>a) 2x <span>= <span>3 <span>is <span>true <span>only <span>for <span>x <span>= 3/2</span></span></span></span></span></span></span></span></span><span> b) x</span>2 + x – <span> 6 = 0 is true only for x = 2, -3</span> Note: for simplicity a conditional equation is called an equation.Identity:<span>It is an equation which holds good for all value of the variable e.g;</span><span>a) (a <span>+ <span>b) x</span></span></span><span>ax + bx is an identity and its two sides are equal for all values of x.</span><span> b) (x + 3) (x + 4)</span> x2<span> + 7x + 12 is also an identity which is true for all values of x.</span>For convenience, the symbol „=‟ shall be used both for equation and identity. <span>1.2 Degree <span>of <span>an Equation:</span></span></span>The degree of an equation is the highest sum of powers of the variables in one of theterm of the equation. For example<span>2x <span>+ <span>5 <span>= <span>0 1</span></span></span></span></span>st degree equation in single variable<span>3x <span>+ <span>7y <span>= <span>8 1</span></span></span></span></span>st degree equation in two variables2x2 – <span> <span>7x <span>+ <span>8 <span>= <span>0 2</span></span></span></span></span></span>nd degree equation in single variable2xy – <span> <span>7x <span>+ <span>3y <span>= <span>2 2</span></span></span></span></span></span>nd degree equation in two variablesx3 – 2x2<span> + <span>7x + <span>4 = <span>0 3</span></span></span></span>rd degree equation in single variablex2<span>y <span>+ <span>xy <span>+ <span>x <span>= <span>2 3</span></span></span></span></span></span></span>rd degree equation in two variables<span>1.3 Polynomial <span>Equation <span>of <span>Degree n:</span></span></span></span>An equation of the formanxn + an-1xn-1 + ---------------- + a3x3 + a2x2 + a1x + a0<span> = 0--------------(1)</span>Where n is a non-negative integer and an<span>, a</span>n-1, -------------, a3<span>, a</span>2<span>, a</span>1<span>, a</span>0 are realconstants, is called polynomial equation of degree n. Note that the degree of theequation in the single variable is the highest power of x which appear in the equation.Thus3x4 + 2x3 + 7 = 0x4 + x3 + x2<span> <span>+ <span>x <span>+ <span>1 <span>= <span>0 , x</span></span></span></span></span></span></span>4 = 0<span>are <span>all <span>fourth-degree polynomial equations.</span></span></span>By the techniques of higher mathematics, it may be shown that nth degree equation ofthe form (1) has exactly n solutions (roots). These roots may be real, complex or amixture of both. Further it may be shown that if such an equation has complex roots,they occur in pairs of conjugates complex numbers. In other words it cannot have anodd number of complex roots.<span>A number <span>of the <span>roots may <span>be equal. Thus <span>all four <span>roots of x</span></span></span></span></span></span>4 = 0<span>are <span>equal <span>which <span>are <span>zero, <span>and <span>the <span>four <span>roots <span>of x</span></span></span></span></span></span></span></span></span></span>4 – 2x2 + 1 = 0<span>Comprise two pairs of equal roots (1, 1, -1, -1)</span>
Answer:
There are 24 nickels
Step-by-step explanation:
Let x represent the number of nickels
Let y represent the number of quarters
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Value Value
Type Number of of
of of each all
Coin Coin Coin Coin
—————————————————————
Nickels | x | $0.05 | $0.05x
Quarters | y | $0.25 | $0.25y
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Totals 28 ——— $2.20
•••••••••••••••••••••••••••••••••••••••••••••••••
The first equation comes from the “Number of coins” column.
(Number of nickels) + (Number of quarters) = (total number of coins)
Equation: x + y = 28
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The second equation comes from the “value of all coins” column.
(Value of all nickels) + (Value of all quarters) = (Total value of all coins)
0.05x + 0.25y = 2.20
Remove the decimals by multiplying each term by 100:
5x + 25y = 220
—————————————————————
So we have the system of equations:
{x + y = 28
{5x + 25y = 202
Solve by substitution. Solve the first equation for y:
x + y = 28
y = 28 - x
Substitute (28 - x) for y in 5x + 25y = 220
5x + 25 (28 - x) = 220
5x + 700 - 25x = 220
-20x + 700 = 220
-20x = -480
x = 24
The number of nickels is 24.
————————————————————
Substitute in y = 28 - x
y = 28 - (24)
y = 4
The number of quarters is 4.
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Checking:
24 nickels is $1.20 and 4 quarters is $1.00
That’s 28 coins.
Indeed $1.20 + $1.00 = $2.20
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