The keypad to the lock to the computer lab has 5 buttons. An access code is a sequence of 3 buttons or 4 buttons. Find the number of access codes: (a) If a button may be repeated. (b) If a button may not be repeated.

(a) 750 codes

(b) 180 codes

Step-by-step explanation:

The number of possible access codes is given by the number of ways to pick 3 out of 5 buttons added to the number of ways to pick 4 out of 5 buttons, in which the order matters.

(a) If a button may be repeated.:

There are 750 possible codes.

(b) If a button may not be repeated.

There are 180 possible codes.

answer: a

step-by-step explanation:

if xy ~ yz therefore xy would be the same length as yz

this story was prepared by jim

mccullaugh in los angeles and

al stewart in new york.

new york the colossal success of "top gun" appears to have dramatically altered madison avenue's

perception of corporate sponsorship

of home video projects.

the paramount home video re- lease, featuring a 60- second diet

pepsi spot, was by no means the

first prerecorded video to carry an advertiser's plug, but it was the

first major theatrical release to do so. in the aftermath of the title's

success, paramount is widely ex- pected to ink a similar deal for

"crocodile dundee" or "star trek

iv" or both.

corporate america's new attraccds push british

recording sales

to 19% gain

london fueled by the compact

disk boom, the value of u.k. manu- facturer shipments of recordings

rose 19% in the 12 -month period ended march 1987, according to the

british phonographic industry.

total value of u.k. shipments for

the period was $755 million for all

configurations. (all value figures

are based on an exchange rate of

$1.68 to the pound sterling.)

cd sales totaled 10.7 million units

worth $121.3 million- compared

with 3.7 million units worth $39.5

million in the prior 12 months -and

accounted for two -thirds of the

overall gain in trade value. at present growth rates, says the bpi, cd

sales for calendar 1987 will reach 20

(continued on page 79)

step-by-step explanation: