Algebra standard deviation

Question

The average math score on the SAT for Melon Valley High School is 500. The standard deviation is 25 points. If 300 students take the test how many students will score between 475 and 525? Question 4 options:

284

340

204

50%

Answer 1

Assuming the scores are more or less normally distributed, we'd expect about $68\%$ of the scores to be within one standard deviation from the mean: $$300\times0.68 = 204$$