Answer :
First, find out how much one biscuit costs. As there are 5 biscuits, you divide the total (30) by 5. 30 / 5 = 6. One biscuit costs 6p.
Now that you know how much one biscuit costs, you times your result by 7. 6 X 7 = 42. 7 biscuits cost 42p.
Now that you know how much one biscuit costs, you times your result by 7. 6 X 7 = 42. 7 biscuits cost 42p.