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

The messenger should use addition and Subtraction instead of multiplication and division

Step-by-step explanation:

It is given that,

A biker can ride a bicycle 18 miles in 3 hours. the messenger estimates that it will take 7 hours to bike 22 miles.

He has done two steps :

step 1: 22-18=4

step 2: 3+4=7

The steps done by the biker are wrong. The correct step should be :

In 1 hour, he should cover (18/3) miles i.e. 6 miles

In 7 hours, he will cover (6×7) miles i.e. 42 miles

It means he should use addition and Subtraction instead of multiplication and division. Hence, the correct option is (c).

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explanation

the graph has a slope of 1/3 because each time you move up 1, you go to the right 3. so, slope = rise/run = 1/3. we can cross choice a off the list since we want a slope of 3, rather than 1/3.

the first table shown has a slope of -3. this is because the rise is -6 and the run is 2, so slope = rise/run = -6/2 = -3. note how x increases by 2 each time (run) and y drops by 6 each time (rise). choice b can be eliminated.

the second table has a slope of 3. each time x goes up by 1, the y values increase by 3. slope = rise/run = 3/1 = 3. alternatively you can use the slope formula to prove that the slope is 3 here. use any two rows of values to generate the two points. choice c is one of the answers

the third table also has a slope of 3. let's use the slope formula to prove as such. i'm going to use the first two rows of the table. so i'll use the two points (2,1) and (5,10)

m = slope

m = (y2-y1)/(x2-x1)

m = (10-1)/(5-2)

m = 9/3

m = 3 so we get a slope of 3

choice d is the other answer