Answer:
The number of textbooks of each type were sold is <u>134 math </u>and <u>268 psychology </u>books.
Step-by-step explanation:
Given:
Total number of math and psychology textbooks sold in a week is 402.
Now, let the number of math textbooks sold be
.
And, the number of psychology textbooks be
.
According to question:


Dividing both sides by 3 we get:

So, total number of math textbooks were 134 .
And, total number of psychology textbooks were 
.
Therefore, the number of textbooks of each type were sold is 134 math and 268 psychology books.
Answer:

Step-by-step explanation:
The square root of a perfect square is a rational number.
So let us take the square root of each number to see which is a rational number.
......irrational
......rational
.........irrational
irrational.
Therefore
is a perfect square
Answer:
$23,360
Step-by-step explanation:
Calculation to determine how much carol originally invested in the account
First step is to divide £23517.60 by 1.025
= (23,517.60)/(1+.025)
= (23,517.60)/1.025
=$22,944
Second step is to add back the $1,000 withdrew
=$22,944+$1,000
=$23,944
Now let calculate how much carol originally invested in the account
$23,944=1.025P
Divide both side by 1.025
P=$23,944/1.025
P=$23,360
Therefore the amount that carol originally invested in the account is $23,360