The annual interest rate is 3.5%.
Solution:
Given Interest (I) = $26.25
Principal (P) = $500
Time (t) = 18 months
Rate of interest (r) = ?
Time must be in years to find the rate per annum.
1 year = 12 months
Divide the time by 12.
Time (t) =
years
Now, find the rate of interest using simple interest formula.
<u>Simple interest formula:</u>






⇒ r = 3.5%
Hence the annual interest rate is 3.5%.
<u><em>Answer:</em></u>
<u>The rule is: </u>
T(x) = 8x + 20
<em><u>Explanation:</u></em>
<u>We are given that:</u>
<u>The rule for the amount that one friend pays is:</u>
C(x) = 2x + 5
<u>Now, we know that:</u>
Each of the four friends will pay the entry fee which is $5 per person
The 4 friends will play the same number of games represented by x
<u>This means that:</u>
We can simply get the rule for the total amount to be paid by the four friends (T(x)) by multiplying the amount paid by each friend by 4
<u>This means that:</u>
T(x) = 4 * C(x)
T(x) = 4(2x + 5)
T(x) = 8x + 20
Hope this helps :)