Given, number of males =20 number of females and children =20+4=24 Average weight of males =54kg Average weight of females =49kg Average weight of children =30kg Average weight of whole group =4825kg Let the number of females be x, ∴ Number of children =24−x. Now, according to the question, x×49+&(24−x)×30 =(44×4825)−(54×20) [∵ Average =
Sum of terms
Total terms
] ⇒19x=323 ⇒x=
323
19
=17 ∴ Number of females =17 and Number of children =24−17=7 ∴ Difference between number of females and children =17−7=10. females and children =17−7=10.