Stocks and bonds - C

tanyajoseph · Posted: Sat Sep 01, 2007 11:25 am Post subject: Stocks and bonds - C

Over a certain time period, did the number of shares of stock in Ruth's portfolio increase?

1) Over the time period, The ratio of the number of share of stock to the total no. of shares of stocks and bonds in Ruth's portfolio increased.
2) Over the time period, the total number of shares of stocks and bonds in Ruth's portfolio increased.

Can someone explain how to solve this problem??

agps · Posted: Sat Sep 01, 2007 11:56 am Post subject:

Ruth has stcks and bonds, lets call it S and B
you want to know if S increased over a period of time.

1) tells you that S/(S+B) has increased, this can happen in two ways S increases or S+B decreases, that could occur from B decreasing, so not sufficient.

2) tells you that S+B increased, also could mean only that B increased, so not sufficient

if you put the two together, S+B increased, but so did S/(S+B) you know for sure that S must have increased.

Answer C.