⁴⁹C₇ = 85,900,584 this is the total ways if we select 7 numbers out of 49.
among that number only 3 are correct, so ⁷C₃ = 35 are correct
If ⁷C₃ are correct, means the remaining incorrect are ⁽⁴⁹⁻⁷⁾C₄ =⁴²C₄
And the total ways of getting 3 correct numbers is :
⁷C₃ x ⁴²C₄ = 3,917,550
