7. María entrena con una barra olímpica que pesa 35lb. A dicha barra se le puede añadir peso de cada lado con un par de discos del mismo peso. Si la indicación para el entrenamiento con barra de Marfa, es que lo realice con 60 ib de peso y sabiendo que los discos disponibles son de \( 10 \mathrm{lb}, 30 \mathrm{lb} \) y \( 2,5 \mathrm{lb} \). ¿Cuántos discos necesita añadir a la barra? Recuerda que los discos se añaden por pares.

A seamstress is using an old cloth measuring tape marked with units to \( 1 / 8 \) of an inch, but the problem is that the old measuring tape has stretched and always gives a slightly larger measurement. The tape is used to measure the length of a dress pattern and then the same tape is used to measure the width of the same pattern. A length of \( 6 \frac{7}{8} \) inches is measured. a) What can you say about the degree of accuracy of the measurement? b) What can you say about the degree of precision of the measurement?

Carry out the calculations each person is performing and give the correct uncertainty. a) A truck operator estimates the distance from a land fill site to a job site to be 9.4 km . He adds 0.5 km for travel inside the job site and 0.3 km at the land fill site. What are the combined distances and uncertainties?

The length of a piece of ribbon is 250 millimeters. Which is the equivalent length in meters? \[ \begin{array}{l}\text { A. } 25 \mathrm{~m} \\ \text { D. } 2.5 \mathrm{~m} \\ 0.25 \mathrm{~m}\end{array} .025 \mathrm{~m} \] E. 0.0025 m

\begin{tabular}{l} Find the LCM (least common multiple) of 2,10 , and 6. \\ A. 2 \\ B. 30 \\ C. 60 \\ D. 120 \\ E. 1 \\ \hline\end{tabular}

\( 2 + ( - \frac { 11 } { 3 } ) ; \quad - \frac { 1 } { 4 } - ( - \frac { 5 } { 6 } ) - 3 \)