This is an exponential growth problem. Exponential growth can be expressed mathematically in the following way:
.
Parameter a presents initial amount.
Parameter r is percentage increase.
Parameter t is time.
An equation that would describe given problem is:
t is the time in years.
I attached the graph of this function.
$7.50(2)=$15.00 (She takes the taxi twice, and its $7.50 each time she takes it)
$0.45(16)+$0.45(8)=$10.80 (Each mile is $0.45, she goes 16 miles on the way to work, and only 8 miles on the way home. Since she walks half way and takes the taxi the other half. Half of 16 is 8)
$15.00+$10.80=$25.80
Alexis pays $25.00 per day for her taxi rides.
Answer:
(3,1)
Step-by-step explanation:
Let's call the 13¢ stamps a and the 18¢ stamps b:
a+b = 42 and therefore a= 42-b (formula 1)
0.13a+0.18b= 6.66 In this formula, substitute the value of a according to formula 1:
0.13(42-b)+0.18b= 6.66 Multiply on the left to get rid of the parenthesis:
5.46-0.13b+0.18b= 6.66 Subtract 5.46 from both sides:
-0.13b+0.18b= 1.20 Add on the left:
0.05b= 1.20 Divide both sides by 0.05
b= 24 You have 24 18¢ stamps and:
42-24= 18 13¢ stamps
Check: (24 x 0.18) + (18 x 0.13)= 6.66 Correct.
