Eleanor practiced playing his violin for 12 minutes. He has practiced 40% of the amount of time he needs to practice today how many more minutes does Eleanor need to practice today?

18 mins

Step-by-step explanation:

if 12mins is 40%

then add 12mins again

12+12=24

so 24 is 80%

then divide 12 by 2 and add it to 24

12/2=6

24+6=30

eleanor practiced 30 mins with his violin per day

he has practiced 12 mins out of 30mins

so he has 18 mins more to practice