$7.50 admission; 20% off
If you were getting 20% off of a £7.50 admission the new price would be £5.This is due to the fact that 10% is 0.75 You can get 10% by dividing the number by 10.10% doubled to get 20% is £1.507.50 minus the 20% off, 1.50, would be £5.