Working mothers who earn $30,000 or less per year receive a rebate on before and after school care of 75%, plus a school bonus of $6,000 that only applies to this category of earnings. Each dollar earned above this amount and up to $40,000 reduces the rebate to 55%, and for any amount above this, the rebate drops to 30%. There are three mothers – Jade earns $40,001, Emily earns $38,000 and Lucy earns $29,550. $, , ? *

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.

a - base

b - exponent

so,