It turns out that 5% of 400 is 20.
(1/20)*400=20.
So Ian was being paid £400 a week before he was given a pay rise.
Yes. There is sixteen ounces in a pound. At thirty cents an ounce, you can buy a pound for $4.80. That also leaves $.20.
Written as a power of ten is 256.×10^0 or 2.56×10^1
