Answer: a) yNA/100
b) NA(y-x)/100
c) (NA)/B
Step-by-step explanation:
a) The total amount of dollars owned by the shares' owner = N number of shares × A dollars per share = NA dollars
This total is then transferred to buy B shares which then appreciates by y%.
The amount of increase in portfolio from January to June = y% of total dollars invested = y% of NA dollars = yNA/100
b) If the shares were left with A, the increase in portfolio from January to June would be x% and = x% of the total Dollar amount = x% of NA dollars = xNA/100
How much more money made in that time would be the difference in interest, between taking the dollars to invest in share B or keeping the dollars on investment A
That is, (yNA/100) - (xNA/100) = NA(y-x)/100
c) Total dollars available after sale of the A stock = NA
Number of B stock this dollar can buy = Total dollars available/amount of B stock per share
That is, (NA)/B
QED!