Through the poublicity of road -safety programme, the street accidents in Purulia district are decreased by 10% in comparison to its previous year. If the number of street accidents in this year be 8748, then find the number of street accidents 3 years before in the district.

Explanation

Let the before 3 years the number of road accidents was x.
Rate of decrease of accidents `=10%` per annum.
`:.` The number of road -accidents in the present year
`=x xx(1-10/100)^(3)=x xx(1-1/10)^(3)=x xx(9/10)^(3)`
As per question `x xx(9/10)^(3)=8748`
`impliesx xx(9xx9xx9)/(10xx10xx10)=8748`
`impliesx=(8748xx10xx10xx10)/(9xx9xx9)`
`implies x=12000`
Hence the required number of road accidents was 12000 before 3 years.