Video Transcript
The graph shows the marks that a student attained in English tests over five months. Given that the test in March was out of 60, what percentage of marks did the student get?
The horizontal axis on the graph shows five months, October, November, December, March, and April. We’re interested in the result for March. This is the fourth dot from left to right. The vertical axis tells us the number of marks attained in each of the five months. The point that we’re interested in is the one circled. Reading across, we can see that this is halfway between 10 and 20. The midpoint of 10 and 20 is 15. Therefore, the student attained 15 marks in March.
We’re told that the March test was out of 60. We can write this as a fraction as 15 over 60 or 15 divided by 60. In order to convert any fraction into a percentage, we need to multiply it by 100, as the word percent means out of 100. We could type this directly into our calculator. Alternatively, we could simplify the fraction 15 over 60 first. 15 and 60 have a common factor of five. Therefore, we can divide the numerator and denominator by five. Remember, whatever you do to the top, you must do to the bottom. 15 divided by five is equal to three. And 60 divided by five is equal to 12. The fraction 15 over 60 is the same as three over 12.
We can simplify this fraction once more by dividing the top and bottom by three. Three divided by three is equal to one. And, 12 divided by three is equal to four. The fraction 15 out of 60 or 15 sixtieths, in its simplest form, is equal to one-quarter or one-fourth. In order to calculate the percentage for March, we need to multiply one-quarter by 100 or find one-quarter of 100. This is equal to 25. Therefore, the student attained 25 percent in the test in March.
