Formula to calculate total amount in a compound interest question is provided in GCE O-Level E-Maths examinations so students don't have to memorise.
It is therefore important for students to know how to use the compound interest formula.
Notice in these two questions, the frequency of compounding affects the value of r and n so it affects the total amount as well.
I always share with my students in my weekly O-Level Maths tuition classes to put themselves in the shoes of a banker who helps their client to grow their money. The frequency of compounding is just like the frequency they meet their client and at each meeting they need to inform how much rate their money has grown based on the frequency of compound.