James takes up dancing for fitness.  He loses twice as many calories per hour as he did when he was walking.  He dances twice a day for .5 hours each time and he does this 4 times a week.  He burned 300 calories an hour walking.  How many calories does he lose a week from dancing?
He burns 2*300=<<2*300=600>>600 calories an hour
He dances for .5*2=<<.5*2=1>>1 hour per day
So he burns 600*1=<<600=600>>600 calories per day
So he burns 600*4=<<600*4=2400>>2400 calories per week
#### 2400