Question 751517
rent  of two room apartment is $700 pm and 3 room apartment is $900
total apartment remain vacant are 6
loss was $4600
let x  2 room apartment
and y  3 room apartment 
 x+y +6  i
700 x+900 y  =4600 ii
multiply first equation by 700 we will get 
700x+900 y=4200 iii
by solving eqn ii and iii
we will get  x=4
and y=2
ANSWER 2 room apartment vacant are 4
       3 room apartment vacant are 2