Question

Jabari owns 100 shares of Stock A and 45 shares of Stock B. For the past month, his stocks have been fluctuating inversely each week. Stock A decreased by m cents per share and Stock B increased by n cents per share. Which equation can be used to find the total change in value of Jabari's shares?

Answer 1

Multiplying by 0.01 to convert cents into dollars, we get:

$100(0.01m)+45(0.01n)\\m+.45n$

Answer 2

The correct answer is:

Let y be the total change in Jabari's shares. There are 4 weeks in a month; this means the equation would be: y = (-1m + 0.45n)4 = -4m + 1.8n.

Explanation:

Jabari has 100 shares of Stock A, and it decreased by m cents per share per week. We represent the fact that it decreased by m cents instead of dollars as 0.01m, since 1 cent is 0.01 dollars. Since there are 100 shares, we multiply this by 100: 100(0.01m) = 1m. Since the value decreases, this is -1m.

He has 45 shares of Stock B, and it increased by n cents per share per week. We represent the fact that it decreased by n cents instead of dollars as 0.01n, since 1 cent is 0.01 dollars. Since there are 45 shares, we multiply this by 45: 45(0.01n) = 0.45n. Since the value increases, this is positive 0.45n.

Together, this gives us a change for one week of -1m+0.45n. However, we are looking at a month, which has 4 weeks. This means we multiply this by 4:

y = (-1m + 0.45n)(4)

Using the distributive property,

y = -1m(4) + 0.45n(4)

y = -4m + 1.8n