Explanation:
x = loser stock investment amount
70 000 - x = gainer investment amount
5% is .05 in decimal 13% is .13 in decimal
- .05 ( x) + .13 (70 000 - x ) = 2800 <=====solve for 'x'
- .05x + 9100 -.13x = 2800
- .18x = - 6300
x = $ 35000 the gainer amount was then also $ 35000
( since they sum to 70000)