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**7.**Jennifer likes to drink black tea. One day, a friend tells her that tea tastes very good with a few drops of freshly squeezed lemon. Jennifer decides to test it the next morning. As the water starts to boil, she squeezes out a lemon and puts a teabag in the cup.

Jennifer has the following information as a math-ace in her class:

- The cup has a capacity of 10 cl.

- The tea bag has a volume of 1 cl.

- She has 1 cl of lemon, which she wants to give in the tea (temperature: 20 ° C).

- She has 8 cl of hot water (temperature: 100 ° C).

- She knows she needs exactly 5 minutes to make her school sandwiches.

Jennifer now faces the following question:

When does my tea get cold faster? If I put the lemon in the cup right away, or if I do that after I made the school sandwiches?