A box contains 12 balls of which 5 are red, and 7 are blue. If 4 balls are drawn from the box, in how many ways can this be done if 1 is red and 3 are blue?

175 ways

Step-by-step explanation:

5 balls are red, and 7 balls  are blue making a total of 12 balls.

4 balls are drawn from the box,

1 ball is red and 3  balls are blue out of the 4 drawn from the box.

We have to choose 1 ball from 5 red balls and 3 blue balls from 7 blue balls.

Since the order is not essential we use combinations to find out

5C1 * 7C3= 5*35 = 175 ways

d) by the cross product property, ab^2 = bc multiplied by ad

step-by-step explanation:

we are given

in the given triangle abc

angle a is 90° and segment ad is perpendicular to segment bc

we can see that

triangle(abc) and triangle(abd) are similar because they have common side and same angle (90 degree)

so, triangles(abc) and abd are similar

since, they are similar

so, the ratio of their sides must be equal

we get

now, we can cross multiply

and we get

so, this could be step to prove it