Since there are 60 questions in the test and she managed to answer 70% of the questions correctly, that means that she answered 70% out of 60 questions correctly.
So you need to calculate how much 70% out of 60 is. Since % is always measured on a base from 0 (%) to 100(%), then 70% is equal to the fraction 70/100, simplified to 7/10. To know how much 7/10 out of 60 is,you just multiplie them and your answer will be 42.
Since the surface area of a cube is 6 times the square of the side length of the cube, then that means the surface area of a cube that has a side length of 5 has a surface area of 6 x 5 x 5. 5 times 5 = 25, and 25 x 6 = 150
