The three numbers have a sum of 30 and therefore a mean of 10 . Use software to determine the standard deviation. Use the function for sample standard deviation. Give your answer precise to two decimal places. standard deviation = Now suppose a fourth value equal to the mean, 10, were added to the data set. What would happen to the standard deviation? The standard deviation would remain the same because the fourth value is equal to the mean. The standard deviation would increase because the data get more spread out relative to the mean. The statiation would decrease because the data get less spread out relative to the mean.

- \( 3^{x+1}+3^{x-2}=k \cdot 3^{x} \quad k= \) ?

Mahtab and Shuvo want to play the \( 3 \times 3 \) ordered "Tic- Tac-Toe", where the cells are numbered. Mahtab won the toss and decided to start the game with a cross. In this case, how many total permutations are possible in the \( 3 \times 3 \) grid where Mahtab can win with only 4 crosses?

2. Given: \( 5 x^{4}-3 x^{3}-x^{2}+x-5 \quad \) All \( \mathbf{R} \) (a) How many terms are there in this expression? (b) Write down the variable in this expression. (c) Write down the constant term. (d) Write down the coefficient of... (e) What is the degree of this expression? \( x \)

Show the type of each of the following triangles according to its angles if its vertices are : \begin{tabular}{ll|l}\( 1 \mathrm{~A}(2,1), \mathrm{B}(4,-2) \) and \( \mathrm{C}(7,5) \) & a \( \mathrm{A}(3,5), \mathrm{B}(-1,1) \) and \( \mathrm{C}(5,-5) \)\end{tabular}

24. The monthly profit of a salon ( \( \$ P) \) is given by \[ P=130 n-15000 \text {, } \] where \( n \) is the number of customers visiting the salon in that month. The profit of the salon is \( \$ 50000 \) last month. If the number of customers increases by \( 30 \% \) this month, find the percentage change in the monthly profit. New \( n(1+30 \%) \times 130-15000 \%=30500 \)