12) ¿Cuántos números de 3 cifras que siempre empiecen y terminen en cifra par existen? \( \begin{array}{llll}\text { A) } 168 & \text { B) } 169 & \text { C) } 180 & \text { D) } 200\end{array} \)

Si el ratio de alumnos a maestras es 4:1 y hay 12 alumnos, ¿cuántas maestras hay?

2. In Buffalo, New York, the temperature was \( { }^{-1} 4^{\circ} \mathrm{F} \) in the morning. If the temperature dropped \( 7^{\circ} \mathrm{F} \), what is the temperature now?

A store sells 2.75 liters of juice in one bottle and 1.25 liters in another. How many liters of juice do you have altogether?

6. (10 points) Consider the sum \( \sum_{k=1}^{4}(2 k+1) \). (a) Write out the sum in expanded form. (b) Calculate the value of the sum.

Write the number \( 1.1 \times 10^{4} \) in standard form. Answer Attempt 1 out of 2