Answer: 3:1
Step-by-step explanation:
Since the jewellery shops sell 240 necklaces in a month and 180 of the necklaces were sold via the shop's website, this means that (240 - 180) = 60 necklaces were sold in a high street shop.
Therefore, the ratio of online sales to shop sales will be:
= 180 / 60
= 3 / 1
= 3:1