Hey there! So,to do this, I would recommend making the fractions into decimals. 1/5 is equal to 0.2 so you multiply that times 70 runners . This equals 14 runners who dropped out. Subtract those who dropped out from the total and now you have 56 runners left. 4/7 as a decimal is about 0.575. Times that by 56 and you get another 32 who dropped out. You're now down to only 24 runners who finished the race.