Which of the following are progressions? a)permutations b)sequences c)combinations d)series e)probability

b. Sequences

Step-by-step explanation:

The following are progressions:

b. Sequences

We have two sequences - arithmetic progression and geometric progression.

A sequence is an arithmetic sequence if the two consecutive numbers have a common difference.

A sequence is a geometric sequence, if the ratio of two consecutive numbers is common.

The sum of the terms of a sequence is called a series. So, in a rather informal way, this can also be considered.

step-by-step explanation:

i believe its "c" because all of the other options include a but it could be d because there is a way of financing with cash at certain places but its uncommon.

we have three similar triangles, because each has a right angle and shares an angle.   let's write the angles in order: opposite to short leg, long leg, hypotenuse.

cab similar to bad similar to cbd

or as ratios,

ca: ab: cb = ba: ad: bd = cb: bd: cd

we also know

ac = ad + cd

(ad+cd): ab: cb = ba: ad: bd = cb: bd: cd

(ad+cd)/cb=cb/cd

we have cb=6, ad=5 and seek x=cd.

we reject the negative root and conclude x=4

answer: 4