Question

I cannot spend more than $35 at the school book fair posters are $5 how many books could i buy if they are &6.50 each

Answer 1

Given  

I cannot spend more than $35

school book fair posters are $5

book cost is $ 6.50 each

Find out how many books i buy.

To proof

let the number of books buy = x

As given in question the money spend in school book fair is not more than $35.

Cost of posters = $5

i.e the money spend in buying poster = $5

cost of each book = $6.50

thus the equation becomes

$Posters\ cost + Number\ of\ books\times each\ book\ cost \leqslant 35$

put these all the values in the above equation

we get

5 + 6.50x ≤ 35

Now

First put x = 1

thus

5 + 6.50 ≤ 35

11.50 ≤ 35

it satisfied the condition

if x =2

we get

5 + 2× 6.50 ≤ 35

18 ≤ 35

it  satisfied the condition

if  x =3

we get

5 + 3 × 6.50 ≤ 35

24.5 ≤ 35

it satisfied the condition

if x = 4

we get

5 + 4×6.50 ≤ 35

31 ≤ 35

it satisfied the condition

if  x = 5

5 + 5× 6.50 ≤ 35

$37.5\nleqslant 35$

this do not satisfied the condition of not spending more than $35 in school book fair.

thus the number of books buy in school fair are 4.

Hence proved