4. The top soil is sold in bags of 5 dm3 at R455,75 per bag. Note that 1 dm3 =
0,001 m3 and 1 decimeter (dm) =
meter.
10
Determine how many bags of top-soil Laura should buy. Show all calculations.

5.
Determine what percentage of the top-soil that Laura will buy will not be used.
(4)

solution:

the given function is ,

      =

the three roots of this quadratic function is , 0 ,8 and 10.all the roots are real and rational.

if a quadratic equation is of the form ,

sum of the roots = a + b +c= 0+8+10=18=  

product of roots taken two at a time = a b + b c+ c a = 0+80+0=80 =  

product of roots = a b c = 0=  

there are 11 doors in a hall starting from 0 to 11.the entry in the hall is permitted through gate number 0 and exit is allowed through only gate number 8 and 10.so, three roots(0,8,10) of quadratic function is given by entry and exit route of this hall.

i believe the answer is c.