In order to find how many additional workers are needed to staff the extra crews you first need to calculate how many workers are on a crew. There are 20 workers at the company now and that's enough to staff 5 crews so there are \( \frac{20}{5} \) = 4 workers on a crew. 10 crews are needed for the busy season which, at 4 workers per crew, means that the roofing company will need 10 x 4 = 40 total workers to staff the crews during the busy season. The company already employs 20 workers so they need to add 40 - 20 = 20 new staff for the busy season.

If the tiger has consumed 48 pounds of food in 4 days that's \( \frac{48}{4} \) = 12 pounds of food per day. The tiger needs to consume 108 - 48 = 60 more pounds of food to reach 108 pounds total. At 12 pounds of food per day that's \( \frac{60}{12} \) = 5 more days.

To fill a 8 gallon tank exactly halfway you'll need 4 gallons of fuel. Each fuel can holds 1 gallons so:

cans = \( \frac{4 \text{ gallons}}{1 \text{ gallons}} \) = 4

To simplify a radical, factor out the perfect squares:

\( \sqrt{18} \)
\( \sqrt{9 \times 2} \)
\( \sqrt{3^2 \times 2} \)
3\( \sqrt{2} \)

The equation for this sequence is:

a_n = a_n-1 + 9

where n is the term's order in the sequence, a_n is the value of the term, and a_n-1 is the value of the term before a_n. This makes the next number:

a₆ = a₅ + 9
a₆ = 37 + 9
a₆ = 46