# The number of book purchased in the year given in table.

### Precalculus: Mathematics for Calcu...

6th Edition
Stewart + 5 others
Publisher: Cengage Learning
ISBN: 9780840068071

### Precalculus: Mathematics for Calcu...

6th Edition
Stewart + 5 others
Publisher: Cengage Learning
ISBN: 9780840068071

#### Solutions

Chapter 2.4, Problem 28E
To determine

## To fill: The number of book purchased in the year given in table.

Expert Solution

The table shows the number of books purchased by the collector in that particular year.

 Year Number of books Year Number of books 1980 420 1995 1020 1981 460 1997 1100 1982 500 1998 1140 1985 620 1999 1180 1990 820 2000 1220 1992 900

### Explanation of Solution

The given table is,

 Year Number of books Year Number of books 1980 420 1995 __ 1981 460 1997 __ 1982 __ 1998 __ 1985 __ 1999 __ 1990 __ 2000 1220 1992 __

A rare book collector purchased 40 books per year between the year 1980 to 2000.

As from the given table up to year 1980 he purchased 420 books and after that he started adding 40 more books each year in his collection of rare books.

So, the formula to calculate the total number of books purchased by the rare book collector in any year is,

{Totalnumberofbookspurchasedinyearx}=Bookpurchasedinyear1980+(x1980)(40) (1)

Substitute 1982 for x in equation (1) 420 for number of books purchased in year 1980 to calculate the number of books purchased in year 1982.

Totalnumberofbookspurchasedinyear1982=420+(19821980)(40)=420+2(40)=420+80=500

Substitute 1985 for x in equation (1) 420 for number of books purchased in year 1980 to calculate the number of books purchased in year 1985.

Totalnumberofbookspurchasedinyear1985=420+(19851980)(40)=420+5(40)=420+200=620

Substitute 1990 for x in equation (1) 420 for number of books purchased in year 1980 to calculate the number of books purchased in year 1990.

Totalnumberofbookspurchasedinyear1990=420+(19901980)(40)=420+10(40)=420+400=820

Substitute 1992 for x in equation (1) 420 for number of books purchased in year 1980 to calculate the number of books purchased in year 1992.

Totalnumberofbookspurchasedinyear1992=420+(19921980)(40)=420+12(40)=420+480=900

Substitute 1995 for x in equation (1) 420 for number of books purchased in year 1980 to calculate the number of books purchased in year 1995.

Totalnumberofbookspurchasedinyear1995=420+(19951980)(40)=420+15(40)=420+600=1020

Substitute 1997 for x in equation (1) 420 for number of books purchased in year 1980 to calculate the number of books purchased in year 1997.

Totalnumberofbookspurchasedinyear1997=420+(19971980)(40)=420+17(40)=420+680=1100

Substitute 1998 for x in equation (1) 420 for number of books purchased in year 1980 to calculate the number of books purchased in year 1998.

Totalnumberofbookspurchasedinyear1998=420+(19981980)(40)=420+18(40)=420+720=1140

Substitute 1999 for x in equation (1) 420 for number of books purchased in year 1980 to calculate the number of books purchased in year 1999.

Totalnumberofbookspurchasedinyear1998=420+(19991980)(40)=420+19(40)=420+760=1180

Fill all the solutions in the given table.

 Year Number of books Year Number of books 1980 420 1995 1020 1981 460 1997 1100 1982 500 1998 1140 1985 620 1999 1180 1990 820 2000 1220 1992 900

The table shows the number of books purchased by the collector in that particular year.

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