Q1. Given [A] =

then [A] is  a (an) ______________  matrix.

diagonal

identity

lower triangular

upper triangular

Q2. A square matrix [A] is lower triangular if

Q3. Given 

, 

then if [C] = [A] [B], then c₃₁= ____________?

-58.2

-37.6

219.4

259.4

Q4. The following system of equations has _______ solution(s).

        x + y = 2

        6x+6y =12

infinite

no

two

unique

Q5 . Consider there are only two computer companies in a country.  The companies are named Dude and Imac.  Each year, Dude keeps 1/5^th of its customers, while the rest switch to Imac.  Each year, Imac keeps 1/3^rd of its customers, while the rest switch to Dude.  If in 2003, Dude had 1/6^th of the market and Imac had 5/6^th of the market, what will be the share of Dude computers when the market becomes stable?

37/90

5/11

6/11

53/90

Q6. Three kids - Jim, Corey and David receive an inheritance of $2,253,453.  The money is put in three trusts but is not divided equally to begin with.  Corey's trust is three times that of David's because Corey made an A in Dr. Kaw’s class.  Each trust is put in an interest generating investment.  The three trusts of Jim, Corey and David pays an interest of 6%, 8%, 11%, respectively.  The total interest of all the three trusts combined at the end of the first year is $190,740.57.  The equations to find the trust money of Jim (J), Corey (C) and David (D) in a matrix form is