Let’s suppose that for the month of December, ESPN’s stock decreased from $88 to $78 per share and NBC’s stock decreased from $48 to $45 per share

let x = number of ESPN shares purchased

y = number of NBC shares purchased

Total amount tnvested = number of shares * price per share

88x + 48y = 20,680................(1)

at the end of the month total sale value = 18870

so, 78x + 45y = 18870...........(2)

Multiply the Equation 1 with 45 and Equation 2 48

(88*45)x + (48*45y) = (20,680*45)...........(3)

(78*48)x + (45*48y) = (18,870*48)...........(4)

(3) - (4)

3960x + 2160y = 930,600

-3744x - 2160y = - 905,760

216x = 24,840

so x = 24,840 / 216

so number of ESPN shares Purchased (x) = 115

by substituting the value of x in Equation (1)

(88*115) + (48*y) = 20,680

48y = 10560

y = 10560 / 48

Number of NBC shares Purchased = 220

ESPN = one hundred fifteen

NBC = two hundred twenty