Two friends buy identical coffees at their favorite coffee shop and receive iden

Question

Two friends buy identical coffees at their favorite coffee shop and receive identical pitchers of cream. Both coffees
are at 100?C. One of them, being impatient, immediately pours the cream into the coffee, and the other does so
after waiting for ten minutes. The temperature of the cream is initially 2?C and after five minutes warms up to
4?C. The coffee without the cream cools down to 90?C after five minutes. The temperature in the coffee shop is
25?C. The volume of each pitcher is one-fourth the volume of one of the coffees. Assume that coffee and cream have
the same specific heat, so that when they are mixed, the temperature of the resulting mixture is a weighted average
of their temperatures, with weights equal to the proportion of their volume in the mixture.
At 10 minutes, immediately after the second friend puts cream into the coffee, they both take a sip of coffee. Who
is drinking the warmer coffee?

Explanation / Answer

the coffee without the creamer is the coolest because based on the volume of its contents, the proportionality of the liquid and temperature is less than that of the creamer with the coffee. So basically the coffee alone is technically cooler.

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