We are given nos of both (senior & junior) and the mean score of juniors, so the mean score of seniors can be found only.
Yes, you can calculate using this but no need as this question needs a logical approach. Without lifting a pen you can know it is choice III only.
Please ask if doubt remains.
aishumurali wrote:
What i meant was the total score of the 20 students ? By multiplying the score by the number of students that got that score for e.g. 70 * 1 + 74 * 3 + 76 * 6 +...+