Andrea can clean a house 4 times as fast as denise. when they work together, andrea and denise can clean a large house in 8 hours. how many hours would it take denise to clean the house by herself?

20
15
40
5

Two fire-lookout stations are 190 miles apart, with station a directly south of station b. both stations spot a fire. the bearing of the fire from station a is upper n 55 degrees upper e and the bearing of the fire from station b is upper s 60 degrees e. how far, to the nearest tenth of a mile, is the fire from each lookout station?

International calls require the use of a country code. many country codes a 3-digit numbers. country codes do not begin with a 0 or 1. there are no restrictions on the second and third digits. how many different 3-digit country codes are possible?

Sarah used her calculator to find sin 125 degrees. she wrote down sin sin125 degrees.57. how could sarah recognize that her answer is incorrect?