Answer:
$9$
Step-by-step explanation:
Given: Thea enters a positive integer into her calculator, then squares it, then presses the $\textcolor{blue}{\bf\circledast}$ key, then squares the result, then presses the $\textcolor{blue}{\bf\circledast}$ key again such that the calculator displays final number as $243$.
To find: number that Thea originally entered
Solution:
The final number is $243$.
As previously the $\textcolor{blue}{\bf\circledast}$ key was pressed,
the number before $243$ must be $324$.
As previously the number was squared, so the number before $324$ must be $18$.
As previously the $\textcolor{blue}{\bf\circledast}$ key was pressed,
the number before $18$ must be $81$
As previously the number was squared, so the number before $81$ must be $9$.
Formula for compound interest is
Interest = Amount - Principal
Interest = - P
Where r = rate in percent
t = time in years
For Jaina,
P = $300
r= 7%
t = 3 yrs
So, Interest = - 300
For Tomas
P = $400
r= 4%
t = 3 yrs
So, Interest = - 400
So pair of equations for Jaina and Tomas are
Interest = - 300
Interest = - 400
Answer: Plan A is less expensive for 50 minutes. About $6 less than Plan B
At 200 minutes, both plans cost $24
Step-by-step explanation:
1.) Look at the numbers for minutes going across the bottom from left to right. Find 50. Follow the grid line up to where the blue line crosses it. (The blue line is lower than the red line so the cost is less.) Look at the numbers on the cost scale to verify the difference if someone asked. Plan A costs $6. Plab B costs $12 for 50 minutes.
2.) Look at where the Red and Blue lines intersect. That is where the plans cost the same amount of money for the same amount of minutes. Follow the grid line down from that point to find the number of minutes.
Answer:
8, 9
Step-by-step explanation:
1/2x + 2(x + 1) = 22
1/2x + 2x + 2 = 22
1/2x + 2x = 20
5/2x = 20
5x = 40
x = 8
8, 9
4 + 18 = 22