Permutations & Combinations
Score range counting
MJAT_TS6_P2
Grade 12
Question:
In an examination: (i) 5 scored ≥95%; (ii) 13 scored ≥90%; (iii) 27 scored ≥85%; (iv) 50 scored ≥80%. Let $m$ = students with [80%,90%) and $n$ = students with [80%,85%). Then $m+n=$
Step-by-Step Solution
Key Concept: $m=50-13=37$ (at least 80% but less than 90%). $n=50-27=23$ (at least 80% but less than 85%). $m+n=60$.
$m+n=\mathbf{60}$.
Correct Answer: 60