47. \( 12,24, x \) तथा 44 का औसत 30 है. \( x \) का मान क्या है ? \( \begin{array}{ll}\text { (A) } 40 & \text { (B) } 42 \\ \text { (C) } 45 & \text { (D) } 46\end{array} \) 48. \( a, b \) और \( c \) का औसत होगा- \( \begin{array}{ll}\text { (A) } \frac{a+b+c}{2} & \text { (B) } \frac{a+b+c}{3} \\ \text { (C) } a+b-c & \text { (D) } a-b+c\end{array} \)

\begin{tabular}{l} Percentages \\ \begin{tabular}{l|l|l|}\hline In this section you will ... \\ - learn to use a multiplier to calculate a percentage increase & Mey words \\ or decrease. \\ In this section, you will learn a more efficient way to calculate \\ percentage increases and decreases. \\ Suppose you want to increase \( \$ 275 \) by \( 65 \% \). \end{tabular} Tip \\ \hline\end{tabular}

In an Arithmetic Progression, the 3rd and 5th terms are 10 and 14 respectively. Find the common difference and the first term.

จงพิสูจน์ว่าให้ \( a \) เป็นจำนวนเต็ม ถ้า \( a \) เป็นจำนวนคู่ หรือ \( a \) เป็นจำนวนคี่ แล้ว \( a+a \) เป็นจำนวนคู่

2. \( [18+3(13-4) 5] \)

1) What percent of 29 is 3 ?