During an athletics training session, Jenny runs 12 laps of a 400-meter track. She wants to run a total of 8 km. How many more laps does she need to run?

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Answer 1 · 2016-10-31T12:30:38

She must run another $8$ laps more.

Each turn gives Jenni, she travels a distance of 400 m. If initially she had run $12$ laps that means she had run a distance of:

$12 laps times 400 m//lap = 4800 m$ .

Jenny wants to run a total distance of $8 km$ , i.e.:

$8 times 1000 = 8000 m$ .

Therefore:

$8000 m - 4800 m = 3200 m$

are still missing to go. If we divide the distance so it runs at every turn, we have

$3200 // 400 = 8$ laps,

which is the number of turns that Jenny remains to run.