Danny = 3 Emilly
danny = 3×7
danny = 21 DVD's

Yes, it's true because the value of LHS = RHS if we solve it .
X=15 because 2(15) is 30-5 is 15
1 lap equals to 3 1/5 minutes what about 6 1/2 cross multiply to get 6 1/2*3 1/5 divide by 1 you get 20 4/5 translated to time is 20 minutes and 48 seconds (4/5*60=48)
20 minutes 48seconds