#### Answer

a) 9.0 qt
b) 88.5 km/h
c) 73 s

#### Work Step by Step

a) 18 has 2 significant figures. The conversion is exact, so it does not affect the amount of sf in the result.
18/2 = 9.000000
Adjusting to 2 sfs: 9.0 qt
b) 55.0 has 3 sfs, 1.609 has 4 sfs. Therefore, the result must have 3 sfs.
55.0 x 1.609 = 88.495
Adjusting to 3 sfs: 88.5 km/h
c) This is a sum, so the number with the least decimal places is 55, so the result must have the same decimal place.
55 + 2.2 + 15.45 = 72.65
Adjusting to decimal places: 73 s