The difference is whether the exponent attaches to just the 2 or to the negative sign as well
-2^4 = - (2x2x2x2) = -16
(-2^4) = -2 x -2 x -2 x -2 = +16
2/5 meters in 1min
2/5=.4
so he goes 1/5 meters in thirty seconds
Meaning it takes him 150 seconds to go a meter
150×6meters=900 seconds to go 6 meters
900/60(seconds in a minute)=15
it takes the snail 15 minutes to go 6 meters
You have 30 more cds than your friend
So it would be your friends CDs + 11 = your CDs, which is 30
n + 11 = 30
