Question

There are two parallel lines, one having $10$ points and the other having $5$ points. The number of triangles formed with vertices as these points is

• A. $225$
• B. $100$
• C. $325$
• D. $125$

Answer 1

The correct option is A $225$

As per question

two parallel lines having $10$ and $5$ points

Therefore the number of triangle formed from two lines ${=}^{10}{C}_2{\times }^5{C}_1$

=$\frac{90}{2}\times 5$

$=225$

Thus the number of triangle formde is $225$.