Welcome to Westonci.ca, the place where your questions are answered by a community of knowledgeable contributors. Our platform connects you with professionals ready to provide precise answers to all your questions in various areas of expertise. Get precise and detailed answers to your questions from a knowledgeable community of experts on our Q&A platform.

37. In an examination, a student's average marks were 63. If he had obtained 20 more marks for his Geography and 2 more marks for his history, his average would have been 65. How many subjects were there in the examination? b. 13 a. 12 C. 11 d. 14​

Sagot :

(total mark/number of subjects)×100=63

(total mark+20+2)/(number of subjects)×100=65

(total mark+22)/number of subjects=0.65

let n be the total number of subjects

((0.63 of 100n)+22)÷(100n)=0.65

because he obtained only 63 percent from sum of all marks.(marks counted from 100)

(0.63×100n+22)÷(100n)=0.65

0.63+(22÷100n)=0.65

0.22÷n=0.65-0.63

0.22÷n=0.02

n=0.22/0.02

n=11

there were 11 subjects