1. Problem: Patricians and plutocrats are in the ratio 2:13, total 315. Find plutocrats.
Formula: If ratio is $a:b$ and total is $T$, then part corresponding to $b$ is $\frac{b}{a+b} \times T$.
Calculation:
$$\text{Plutocrats} = \frac{13}{2+13} \times 315 = \frac{13}{15} \times 315$$
$$= 13 \times \cancel{21} = 273$$
2. Problem: Girls' team outlifted boys' by 140%. Boys lifted 1400 pounds. Find girls' lift.
Formula: Increase by 140% means girls lifted $1400 + 1.4 \times 1400 = 2.4 \times 1400$.
Calculation:
$$\text{Girls} = 2.4 \times 1400 = 3360$$
3. Problem: 15% of flowers are roses, 120 roses. Find total flowers.
Formula: $\text{Total} = \frac{\text{Part}}{\text{Percent}} = \frac{120}{0.15}$.
Calculation:
$$\text{Total} = \frac{120}{0.15} = 800$$
4. Problem: $7 \frac{2}{5}$ of what number is $1 \frac{7}{10}$?
Convert mixed numbers:
$$7 \frac{2}{5} = \frac{37}{5}, \quad 1 \frac{7}{10} = \frac{17}{10}$$
Equation:
$$\frac{37}{5} x = \frac{17}{10}$$
Solve for $x$:
$$x = \frac{17}{10} \times \frac{5}{37} = \frac{85}{370} = \frac{17}{74}$$
5. Problem: What fraction of $14 \frac{1}{4}$ is $\frac{3}{8}$?
Convert:
$$14 \frac{1}{4} = \frac{57}{4}$$
Fraction:
$$\text{Fraction} = \frac{3/8}{57/4} = \frac{3}{8} \times \frac{4}{57} = \frac{12}{456} = \frac{1}{38}$$
6. Solve: $7 \frac{2}{5} x + 5 \frac{1}{3} = \frac{1}{15}$
Convert:
$$7 \frac{2}{5} = \frac{37}{5}, \quad 5 \frac{1}{3} = \frac{16}{3}$$
Equation:
$$\frac{37}{5} x + \frac{16}{3} = \frac{1}{15}$$
Subtract $\frac{16}{3}$:
$$\frac{37}{5} x = \frac{1}{15} - \frac{16}{3} = \frac{1}{15} - \frac{80}{15} = -\frac{79}{15}$$
Solve for $x$:
$$x = -\frac{79}{15} \times \frac{5}{37} = -\frac{395}{555} = -\frac{79}{111}$$
7. Solve: $-[-(-2p)] - 3(-3p + 15) = -(-4)(p - 12)$
Simplify left:
$$-[-(-2p)] = -[2p] = -2p$$
$$-3(-3p + 15) = 9p - 45$$
Left side:
$$-2p + 9p - 45 = 7p - 45$$
Right side:
$$-(-4)(p - 12) = 4(p - 12) = 4p - 48$$
Equation:
$$7p - 45 = 4p - 48$$
Solve:
$$7p - 4p = -48 + 45$$
$$3p = -3$$
$$p = -1$$
8. Graph $x \neq -2$ on number line means all real numbers except $-2$.
9. Evaluate $a^{-3}(a^{-2} - 2a)$ for $a = -2$
Calculate powers:
$$a^{-3} = (-2)^{-3} = -\frac{1}{8}$$
$$a^{-2} = (-2)^{-2} = \frac{1}{4}$$
Expression:
$$-\frac{1}{8} \left( \frac{1}{4} - 2(-2) \right) = -\frac{1}{8} \left( \frac{1}{4} + 4 \right) = -\frac{1}{8} \times \frac{17}{4} = -\frac{17}{32}$$
12. Solve system:
$$4x + y = -5$$
$$2x - y = -1$$
Add equations:
$$(4x + y) + (2x - y) = -5 + (-1)$$
$$6x = -6$$
$$x = -1$$
Substitute $x$:
$$4(-1) + y = -5$$
$$-4 + y = -5$$
$$y = -1$$
13. Solve system:
$$x - 3y = -7$$
$$3x + y = -1$$
Multiply second by 3:
$$9x + 3y = -3$$
Add to first:
$$(x - 3y) + (9x + 3y) = -7 + (-3)$$
$$10x = -10$$
$$x = -1$$
Substitute $x$:
$$-1 - 3y = -7$$
$$-3y = -6$$
$$y = 2$$
14. Solve system:
$$4x - y = -7$$
$$2x + 2y = 4$$
Multiply first by 2:
$$8x - 2y = -14$$
Add to second:
$$(8x - 2y) + (2x + 2y) = -14 + 4$$
$$10x = -10$$
$$x = -1$$
Substitute $x$:
$$4(-1) - y = -7$$
$$-4 - y = -7$$
$$-y = -3$$
$$y = 3$$
15. Multiply $(4x - 3)(x + 2)$
Use distributive property:
$$4x \times x + 4x \times 2 - 3 \times x - 3 \times 2 = 4x^2 + 8x - 3x - 6 = 4x^2 + 5x - 6$$
16. Square $(4x + 3)^2$
Formula: $(a+b)^2 = a^2 + 2ab + b^2$
Calculate:
$$16x^2 + 24x + 9$$
17. Graph $y = -3x$
Line through origin with slope $-3$, downward from left to right.
18. Graph $y = 3x$
Line through origin with slope $3$, upward from left to right.
19. Graph $4 + 3x - y = 0$
Rewrite:
$$y = 3x + 4$$
Line crosses y-axis at 4, slope 3.
20. Simplify $\frac{a/b}{c + x}$
Rewrite:
$$\frac{a/b}{c + x} = \frac{a}{b(c + x)}$$
21. Same as 20.
22. Simplify $\frac{1}{\frac{1}{a + b}}$
Invert denominator:
$$= a + b$$
23. Add $\frac{4}{xyc} - \frac{5m}{xy(c + 1)} - \frac{3k}{xy^2}$
Common denominator is $xyc(c+1)y$ but expression is simplified as is.
24. Add $k + \frac{1}{k}$
Cannot combine further without common denominator.
25. Add $my + \frac{p}{y}$
Common denominator $y$:
$$\frac{my^2 + p}{y}$$
26. Factor $20x^2 m^3 k^6 - 10x m^4 k^4 + 30x^5 m^4 k^6$
Find GCF:
$$10x m^3 k^4$$
Factor out:
$$10x m^3 k^4 (2x - m + 3x^4 m k^2)$$
27. Simplify $\frac{(x^2 y^0)^2 y^0 k^2}{(2x^2 k^5)^{-4} y}$
Simplify powers:
$$y^0 = 1$$
$$(x^2)^2 = x^4$$
Denominator:
$$(2x^2 k^5)^{-4} = \frac{1}{(2x^2 k^5)^4} = \frac{1}{16 x^8 k^{20}}$$
Expression:
$$\frac{x^4 k^2}{\frac{1}{16 x^8 k^{20}} y} = x^4 k^2 \times 16 x^8 k^{20} \times \frac{1}{y} = 16 x^{12} k^{22} \times \frac{1}{y} = \frac{16 x^{12} k^{22}}{y}$$
28. Simplify $\frac{a^0 x^2 x^0}{m^1 y^0 m^{-2}}$
Simplify powers:
$$a^0 = 1, x^0 = 1, y^0 = 1$$
Expression:
$$\frac{x^2}{m \times m^{-2}} = \frac{x^2}{m^{1-2}} = \frac{x^2}{m^{-1}} = x^2 m$$
29. Simplify $\left( \frac{p^2 y}{y} \right) \left( \frac{x^{-1} y}{p^2} \right)$
Simplify inside:
$$\frac{p^2 y}{y} = p^2$$
Expression:
$$p^2 \times \frac{x^{-1} y}{p^2} = x^{-1} y = \frac{y}{x}$$
30. Simplify:
$$-2\{[(-2 - 2) - 3^0(-2 - 1)] - [-2(-3 + 5) - 2]\} - |-2| + \sqrt{-8}$$
Calculate inside:
$$(-2 - 2) = -4$$
$$3^0 = 1$$
$$-2 - 1 = -3$$
$$[-4 - 1 \times (-3)] = [-4 + 3] = -1$$
Second bracket:
$$-3 + 5 = 2$$
$$-2 \times 2 = -4$$
$$-4 - 2 = -6$$
Expression:
$$-2(-1 - (-6)) - 2 + \sqrt{-8} = -2(-1 + 6) - 2 + \sqrt{-8} = -2(5) - 2 + \sqrt{-8} = -10 - 2 + \sqrt{-8} = -12 + \sqrt{-8}$$
Since $\sqrt{-8} = 2i \sqrt{2}$ (imaginary), final answer:
$$-12 + 2i \sqrt{2}$$
Problem Set 64 2759D9
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