explanation

Question

River Ramblet charges $25 per day to rent a kayak. How much will it cost to rent a kayak for 5 days?

 

Write and solve an equation to solve the problem.

Answer 1

C=cost for number of days

d=number of days

 

C=25d

 

if d= 5, C=25*5 = 125

Answer 2

Lets call 'C' the cost to rent the kayak,

 

C = $25/day ($25 per day)

 

lets call 'D' the number of days the person would like to rent the kayak,

 

D = 5 days

 

Lets call T the total cost to rent the kayak

 

T = ??

 

To come up with the equation we can think of other scenarios.  If it costs $25 per day, how much would it cost to rent for one day?

 

$25

 

How much for two days?

 

$25 + $25 = $50

lets factor this...

$25(1+1) = $50

$25*(2) = $50

 

Three days?

 

$25 + $25 + $25 = $75

lets factor this...

$25*(1+1+1) = $75

$25*(3) = $75

 

Four days?

$25 + $25 + $25 + $25= $100
lets factor this...
$25*(1+1+1+1) = $100
$25*(4) = $100

 

 

so in general we can see the equation should be,

 

Cost*days = total cost

 

or

 

C*D = T

 

so for our question where

C = $25/day

D = 5 days

we have

 

($25/day)*5days = $125

 

T = $125