Note the binomial expansion,
(<em>a</em> + 1/<em>a</em>)³ = <em>a</em> ³ + 3<em>a</em> + 3/<em>a</em> + 1/<em>a</em> ³
so
<em>a</em> ³ + 1/<em>a</em> ³ = (<em>a</em> + 1/<em>a</em>)³ - 3 (<em>a</em> + 1/<em>a</em>)
Similarly,
(<em>a</em> + 1/<em>a</em>)² = <em>a</em> ² + 2 + 1/<em>a</em> ²
We're given <em>a</em> ² + 1/<em>a</em> ² = 79, so
(<em>a</em> + 1/<em>a</em>)² - 2 = 79
(<em>a</em> + 1/<em>a</em>)² = 81
<em>a</em> + 1/<em>a</em> = ±9
but <em>a</em> > 0, so we ignore the negative solution.
Then
<em>a</em> ³ + 1/<em>a</em> ³ = 9³ - 3×9 = 702
The answer is the second one 1/2 -3
C.P. = $95000
S.P. = $280000
a. Profit
= S.P. - C.P.
= $280000 - $95000
= $185000
b. Let the profit% of C.P. be x.
(x/100) × $95000 = $185000
=> x/100 = $185000/$95000
=> x/100 = 37/19
=> x = (37/19) × 100
=> x = 3700/19
=> x = 194 14/19
So, profit percent of buying price is 194 14/19%.
c. Let the profit% of S.P. be x.
(x/100) × $280000 = $185000
=> x/100 = $185000/$280000
=> x/100 = 37/56
=> x = (37/56) × 100
=> x = 3700/56
=> x = 925/14
=> x = 16 1/14
So, profit percent of selling price is 16 1/14%.
d. Buying price percentage profit sounds better as far as Ella is concerned.
Answer:
1152-v
Step-by-step explanation:
Answer:
D
Step-by-step explanation:
