Question 70984
problem#10
simplify each complex fraction
(w+3)/(4w) divided by (w-3)/(2w)
Remember when you divide fractions, you invert the dividing fraction & multiply:
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{{{((w+3))/(4w)}}} * {{{(2W)/((w-3))}}}
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Cancel the 2w into the 4w and you have:
{{{((w+3))/2}}} * {{{1/((w-3))}}} = {{{((w+3))/(2(w-3))}}} about as simple as you can get it.
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Problem #28
fungicides account for (1)/(10) of the pesticides used in the United States. The ratio of fungicides to insecticides used in the United States can be written (1)/(10) divided by (1)/(4). Write this ratio in simplest form.
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Invert and multiply by the dividing fraction;
{{{1/10}}} * {{{4/1}}} = {{{4/10}}} = {{{2/5}}}
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Problem #32
The combined resistance of two resistors R1 and R2 in a parallel circuit is given by the formula
Rt = (1)divided by (1)/(r1)+ (1)/(r2)
simplify the formula.
Rt = {{{1/((1/(r1)) + (1/(r2)))}}}
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Put the dividing fractions over a single denominator:
Rt = {{{1/((r2 + r1)/(r1*r2))}}}
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Invert the dividing fractions then multiply by 1 and you have;
rt = {{{(r1*r2)/(r1 + r2)}}}
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The very familiar "product over sum" equation for 2 resistors in parallel.