1. It is not very correct to talk about kinetic energy here. Let's say: internal energy. The heat capacity of the solid body is a complicated question and it is far beyond MCAT(phonon theory)

2. It is possible to analyse this problem with easy math, but with the time frame given, it is best to use bleargh explanation above.

3. However, I show how to do it anyway:

The liquid raise its temperature: so Q= C1 * M1 * (T-T1)

(C1, M1,T1 ) are heat capacity,Mass and initial temp for liquid)

The metal drop its temperature: Q= C2*M2*(T2-T)

Notice that Final temperature the same for liquid and metal, and amount of heat transfer equals Q=Q or

C1 * M1 * (T-T1) = C2*M2*(T2-T)

Let's substitute the numbers from the problem and get how T depend on C2.

We get( I skip arithmetics)

T = (50C2+100C1)/(C2+4C1)

So, if C2(metal heat capacity) and C1 >0 (it is a fact

then nominator is always larger then the denomentor and the function grows if C2 grows. (You can check it with the first derivatives if you'd like)

That means that the larger the C2 the higher the T. As required. But I would not use this method on MCAT. (too time consuming).

Just say, that high heat capacitors can store more internal energy and transfer it to heat.

HTH