(325-120)/2.5=2050/25=82
=>82 students attended the dance
The formula for the triangular sequence is Xn=n(n+1)/2
So X25=25(25+1)/2=325
The answer to this question is -64
Answer:
Need more explanation
Step-by-step explanation:
<span>each question is worth 4 points because if he missed 5 questions and 5*4 is 20 and 20 minus 100 is 80
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