The number of 3-digit numbers, that are divisible by either 3 or 4 but not divisible by 48 ,
is

Total number of 3 digited numbers=900
No’s divisible by 3 = 300 
$\left(U\mathrm{sing}\frac{900}{3}=300\right)$
No’s divisible by 4 =225
$\text{ (Using }\frac{900}{4}=225\text{ ) }$
No’s divisible by 12 = 75
$\text{ (Using }\frac{900}{12}=75\text{ ) }$
No’s divisible by 48 = 18
Total no’s =300+225-75-18
Total no’s=432