The numbers of straight lines can be formed out of 10 points of which 7 are collinear ?Question 4Answera.21b.None of thesec.26d.25

The number of straight lines that can be formed from a set of points is given by the formula nC2, where n is the number of points. This formula is derived from the fact that a line requires two points, and we are choosing 2 points from n.

In this case, we have 10 points, but 7 of them are collinear, which means they all lie on the same line. So, these 7 points can only form 1 line.

The remaining 3 points can form 3C2 = 3 lines.

So, the total number of lines that can be formed is 1 (from the 7 collinear points) + 3 (from the remaining 3 points) = 4 lines.

Therefore, the correct answer is not listed among the options you provided. The correct answer should be 4.