Let four consecutive numbers are
`A=(x),B=(x+1),C=(x+2)+(x+3)`
According to question
Average `=((x)+(x+1)+(x+2)+(x+3))/(4)`
`implies 56.4=(4x+6)/(4)`
`implies 226 = 4x+6`
`implies 4x=226-6=220`
`x=(220)/(4)=55`
`therefore ` Product of A and C
`=(x)xx(x+2)=(55)xx(55+2)=55xx57=3135`
Average of 4 nos.=average of B and C=56.5
Alternate Solution
`because ` B and C consecutive nos.
`therefore B=56,C=57`
`therefore A=55`
`therefore A xx C=3135`
