The length, l cm, of a sheet of paper is 29.7 cm, correct to the nearest millimeter. Complete the statement about the value of l.

Lower bound = $29.7 \text{ cm} - 0.05 \text{ cm} = 29.65 \text{ cm}$

Upper bound = $29.7 \text{ cm} + 0.05 \text{ cm} = 29.75 \text{ cm}$

The value of $l$ is between the lower bound (inclusive) and the upper bound (exclusive).

9. Lucia invests $5000 at a rate of 4.5% per year simple interest. Calculate the value of her investment after 7 years.

The formula for simple interest is $I = P \times R \times T$, where $P$ is the principal, $R$ is the annual interest rate, and $T$ is the time in years. $I = \$5000 \times 0.045 \times 7$ $I = \$1575$

Total value = Principal + Interest $\text{Total value} = \$5000 + \$1575$ $\text{Total value} = \$6575$ The value of her investment after 7 years is \boxed{\6575}$.

10. Rectangle A measures 3 cm by 8 cm. Five rectangles congruent to A are joined to make a shape. Work out the perimeter of the shape.

Each rectangle has dimensions: width = 3 cm, length = 8 cm.
Let's trace the outer edges of the combined shape shown in the diagram.

• There are three horizontal segments at the top of the shape: 3 cm (left), 8 cm (middle), 3 cm (right).
• There are three horizontal segments at the bottom of the shape: 3 cm (left), 8 cm (middle), 3 cm (right). Total horizontal perimeter = $(3 \text{ cm} + 8 \text{ cm} + 3 \text{ cm}) \times 2$ Total horizontal perimeter = $14 \text{ cm} \times 2 = 28 \text{ cm}$.

• There are two outer vertical segments on the far left: 8 cm (top) + 8 cm (bottom).
• There are two outer vertical segments on the far right: 8 cm (top) + 8 cm (bottom).
• There are four inner vertical segments where the central horizontal rectangle connects to the vertical rectangles. Each of these segments is 3 cm (the width of a rectangle). Total vertical perimeter = $(8 \text{ cm} \times 4) + (3 \text{ cm} \times 4)$ Total vertical perimeter = $32 \text{ cm} + 12 \text{ cm} = 44 \text{ cm}$.

Total perimeter = Total horizontal perimeter + Total vertical perimeter
Total perimeter = $28 \text{ cm} + 44 \text{ cm}$
Total perimeter = $72 \text{ cm}$.
The perimeter of the shape is $\boxed{72 \text{ cm}}$.