The "off-peak" weekly average cost of hiring a caravan in Wales is 520. In July the average cost increases to 800. calculate the percentage increase in cost. Give your answer to 2 significant figures.

For this case you can solve the problem by applying a simple rule of three in which we have

520 - - - > 100%

800 - - - > x

Clearing x we have

x = (800/520) * 100 = 154%

the percentage increase in cost was

154-100 = 54%

answer

the percentage increase in cost was 54%