This shows a figure containing a doing diagram. It has three rectangular boxes in the middle, the 1^st containing ‘subtract 300’ linked to the 2^nd box on the right containing ‘multiply by 0.4’, which is linked to the 3^rd box on the right containing ‘add 20’. To the left of the 1^st box is the phrase ‘number of minutes’, linked by an arrow pointing right. On the right of the 3^rdrectangular box is an arrow pointing right to the number 45.

◄ 4.1 Time formula