Is this answer correct? Why? Why not? Reverse Percentages 19/11/2018 WALT: work backwards to calculate original amounts in percentage problems Question A pair of shoes are reduced by 20% in a sale. The sale price is £48. What was the original price? Answer Is this answer correct? Why? Why not? 20% of £48 = £9.60 £48 + £9.60 = £57.60 So, Original price = £57.60

A pair of shoes are reduced by 20% in a sale. The sale price is £48. Question A pair of shoes are reduced by 20% in a sale. The sale price is £48. What was the original price? Answer 20% of £48 = £9.60 £48 + £9.60 = £57.60 So, Original price = £57.60

Reverse Percentages Original Amount 100% value EXAMPLES (a) Mavis paid £48 for shoes that had been reduced by 20% in a sale. What was the original price? 3

Reverse Percentages Original Amount 100% value EXAMPLES (b) George received an 8% pay rise. His new salary is now £19200. What was his original salary? 4

Your Turn 1) A quantity is decreased by 3%. It now has a mass of 38.8kg. What was the original mass? 2) A coat was advertised in a sale at £79 after a 5% reduction. What was the original price? 3) Bobby’s salary was increased by 7%. His new salary after the pay rise is £28,890. What was his original salary? 4) In a local election Labour received 1375 votes. This was 12% up on the previous election. What was their previous number of votes? 5) A charity’s income has been reduced by 12.5%. It’s income is now £49 000 per year. What was it’s previous revenue? 5

Your Turn 1) A quantity is decreased by 3%. It now has a mass of 38.8kg. What was the original mass? 2) A coat was advertised in a sale at £79 after a 5% reduction. What was the original price? 3) Bobby’s salary was increased by 7%. His new salary after the pay rise is £28,890. What was his original salary? 4) In a local election Labour received 1375 votes. This was 12% up on the previous election. What was their previous number of votes? 5) A charity’s income has been reduced by 12.5%. It’s income is now £49 000 per year. What was it’s previous revenue? 40kg £83.16 £27 000 1228 votes £56 000 6

Percentages Problem Solving Miss Cradick wants to go to Essex for the weekend. The cost of a standard return ticket is £111.10. Will it be cheaper for me to buy my ticket with trainline or virgin trains? (Assuming I will pay by credit card) Extension I paid a total amount of £86.84 on my credit card for a ticket from Virgin. What was the cost of the ticket before the credit card charge was added? TrainLine Credit Card Charge 2% of ticket price Booking fee £1.50 Credit card charge 3.5% of ticket price No Booking fee

Percentages Problem Solving 19/11/2018 £111.10 TrainLine Credit Card Charge 2% of ticket price Booking fee £1.50 Credit card charge 3.5% of ticket price No Booking fee     Train line is cheaper by 17p

Percentages Problem Solving 19/11/2018 Extension I paid a total amount of £86.84 on my credit card for a ticket from Virgin. What was the cost of the ticket before the credit card charge was added? Credit card charge 3.5% of ticket price No Booking fee     = £83.90

Do you understand the WALT? I have learned how to … Marking Guide –RAG123 Feedback – End of Lesson Do you understand the WALT? I have learned how to … What went well in today’s lesson? I was able to … during today’s lesson. What didn’t you understand today? I don’t understand … What helped you make progress today? … helped me progress today. What will help you make more progress? I would like to … What do you need to do next? I need to … to make further progress Cymraeg@MartinSant