Keller, Inc. had the following operating segments, with the indicated amounts of segment revenues and segment expenses:

segment	external revenues	intersegment sales	segment expenses
A	6,840,000	585,000	5,760,000
B	2,802,500	1,045,000	3,990,000
C	787,500	1,365,000	2,362,500
D	4,400,000	330,000	4,400,000
E	1,445,000	722,500	2,380,000

a. When totaling the revenues to use as the basis for the 75% rule, what is the 75% hurdle that must be exceeded by the revenues of the reportable segments?

b. Briefly describe the test to determine whether a sufficient number of operating segments are disclosed.