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