Answer:
She originally bought either 20 or 32 shares
Explanation:
An investor bought a number of shares of stock for $1600 after Price dropped by $10 per share she sold all but four of her shares for $1120 how many shares that she originally by?
Let the number of shares she bought be represented by 1600/x
This is calculated as:
1600/x = 1120/x + 10 + 4
Multiply through by (x)(x - 10)
1600(x-10) = 1120(x) + 4(x)(x - 10)
1600x - 16000 = 1120x + 4x² - 40x
Collect like terms
4x² + 1120x - 1600x - 40x +16000 = 0
4x² - 520x + 16000 = 0
Using the Almighty formula method
= -b ± √b²- 4ac/2a
a = 4, b = -520 , c = 16,000
Hence:
= -(-520) ± √-520² - 4 × 4 × 16000/2 × 4
= 520 ± √14400/8
= 520 ± 120/8
520 - 120/8
= 400/8
= 50
520 ± 120/8
= 520 + 120/8
= 640/8
= 80
Since we have:
1600/x
When x = 50
= 1600/50
= 32
When x = 80
= 1600/80
= 20
Therefore, she originally bought either 20 or 32 shares