A biker can ride a bicycle 18 miles in 3 hours. the messenger estimates that it will take 7 hours to bike 22 miles. here is the messengers work: step 1: 22-18=4
step 2: 3+4=7
what mistake did the messenger make?
• the messenger did not make a mistake. the estimate is correct
• the 3 and 4 should have been multiplied instead of added.
• the messenger used addition and Subtraction instead of multiplication and division
• the 22 and 18 should have been divided instead of subtracted
• the 22 and 18 should have been averaged instead of subtracted

On the way home from visiting his family, vincent’s plane cruised at an altitude of 3.2 × 10^4 feet. he had heard that a man named felix baumgartner skydived from an altitude of 1.28 × 10^5 feet. vincent wants to know how much higher felix went on his skydiving trip. question 1 you have already seen how adding numbers works in either scientific notation or standard notation. but can you subtract numbers in scientific notation and get the same results as subtracting in standard notation? to find out, first solve vincent’s problem in standard notation. part a write the cruising altitude of vincent’s plane in standard notation.