How many distinct triangle can be drawn with their vertices selected from 10 points, exactly 5 of which are on one line and remaining 5 are on other parallel line

(Q). How many distinct triangle can be drawn with their vertices selected from 10 points, exactly 5 of which are on one line and remaining 5 are on other parallel line?
Solution:-
¹⁰C₃ – ⁵C₃ – ⁵C₃
= 120 – 10 – 10
= 100      Answer