Sally walks to the store at a rate of 3 m/s for 15 seconds. She stops at a crosswalk for 4 seconds until the sign tells her she can go. Sally ran across the street at 5 m/s for 3 seconds until she reached the other side. She then walked the rest of the way to the store at 3 m/s. If the store was 100 m away from where Sally started originally and it took her 250 seconds to get there, what was her average speed?

Explanation:

step one:

simply put average speed is defined as the total distance travelled divided by the total time taken.

step two:

given data

total distance is the distance from where she started to the store

which is 100 m

also, we are told that the total time taken is 250 seconds

step three:

Hence we can compute the average speed as

average speed= 100/250

average speed= 0.4 m/s  

im sorry i dont know

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