Question Number 101425 by pete last updated on 02/Jul/20

A student wrote three papers in mathematics  examinations. Her marks for the two of  papers were 77 and 72 respectively. To  obtain grade A, an average of not less  than 75 marks is required for the three  papers. How many marks must she get  in the third paper to get grade A?

Commented byRasheed.Sindhi last updated on 02/Jul/20

Arithmatic approach  77=75+2  72=75−3  +2−3=−1  To balance this −1 :  75+1=76  At  least 76 in third paper

Commented bypete last updated on 03/Jul/20

thanks sir

Answered by Rasheed.Sindhi last updated on 02/Jul/20

((77+72+x)/3)=75 ; x: at least marks in 3rd paper  x=75×3−77−72=76

Answered by Rasheed.Sindhi last updated on 02/Jul/20

Let at least marks in 3rd paper:                   75+x;  x∈Z  77=75+2  72=75−3  ? =75+x  +2−3+x=0⇒x=1  75+x=75+1=76

Answered by Rio Michael last updated on 02/Jul/20

Or  75 for 3 papers = 75 × 3 = 225  ⇒  least marks for paper = 225−77−72 = 76 marks

Commented byRasheed.Sindhi last updated on 02/Jul/20

AnOther arithmatic approach.